Submit <button> not submitted with javascript disable

Submit <button> not submitted with javascript disable - javascript

I'm trying to set a element to disable after clicking (after submitting the data). The issue is, when I use the javascript to disable on click, the button is disabled, but does does not submit the information.
function disableButton(btn) {
document.getElementById(btn.id).disabled = true;
alert("Button has been disabled.");
}
<center><button type="submit" id="btn1" name="Submit" onclick="disableButton(this)">Submit</button></center>
Does anyone know how to fix this? I'm not very experienced. I've had it work with the a form, but not as a element.
Thanks.

Try to delay the disabling with a timeout 0. This should disable the button at the end of script's lifecycle, allowing the form to post before :
function disableButton(btn) {
setTimeout( () => {
btn.disabled = true;
}) // No need to set a duration for the timeout
}
<form>
<button type="submit"
onclick="disableButton(this)"
action="/test">Submit</button></form>
Now if you check your console, you see a GET request being made.
Also, <center> is deprecated and not supported in HTML5.

Why don't you try putting the disable function on the form?
Here's the code and site if you are:
** https://www.the-art-of-web.com/javascript/doublesubmit/ **
<form method="POST" action="..." onsubmit="myButton.disabled = true; return true;">
<input type="submit" name="myButton" value="Submit"> </form>
Also, try to use onsubmit.
If you are using js validation you can use this
<form method="POST" action="..." onsubmit="return checkForm(this);">
...
<input type="submit" name="myButton" value="Submit">
</form>
<script type="text/javascript">
function checkForm(form)
{
//
// validate form fields
//
form.myButton.disabled = true;
return true;
}
</script>

If you use addEventListener, you won't have this problem See below for an explanation and examples. Also note that this is a Chrome/Safari specific bug from what I have tested.
What you were doing disables the button during the processing of the click. When the browser checks if it should submit the form, it doesn't (though I haven't found something that says it should in the standard).
If you handle it in the submit event of the form, the check on whether the button was disabled has already passed.
Disables using onclick so you still see it here in this example.
<form>
<button type="submit" action="/test" onclick="this.disabled = true">Submit</button>
</form>
Disables it in the onsubmit handler, so it disappears here in this example.
<form onsubmit="this.querySelector('button').disabled = true">
<button type="submit" action="/test">Submit</button>
</form>
However, as I worked on a version without inline handlers, I realized the (seemingly incorrect) behavior cannot be reproduced when done that way.
I would suggest you use JS event handlers and you should handle the submit event since it is more accurate semantically (and even using addEventListener does not fix the problem in Safari).
function queryRegister(query, eventName, handler) {
document.querySelector(query).addEventListener(eventName, handler);
}
queryRegister("#click-handler-form button", "click", (e) => {
e.target.disabled = true;
});
queryRegister("#submit-handler-form", "submit", (e) => {
e.target.querySelector("button").disabled = true;
});
Both submit without inline handlers
<hr />
button.onclick
<form id="click-handler-form">
<button type="submit" action="/test">Submit</button>
</form>
form.onsubmit
<form id="submit-handler-form">
<button type="submit" action="/test">Submit</button>
</form>

If <button type="submit"> tag is not inside <form></form> there is nothing to submit. <button type="submit"> submits only it's parent <form>

Try to submit the form with Javascript.
function disableButton(btn) {
document.getElementById(btn.id).disabled = true;
document.getElementById('formId').submit();
alert("Button has been disabled.");
}

Related

Javascript timeout problem with Flask backend [duplicate]

In the following page, with Firefox the remove button submits the form, but the add button does not.
How do I prevent the remove button from submitting the form?
function addItem() {
var v = $('form :hidden:last').attr('name');
var n = /(.*)input/.exec(v);
var newPrefix;
if (n[1].length == 0) {
newPrefix = '1';
} else {
newPrefix = parseInt(n[1]) + 1;
}
var oldElem = $('form tr:last');
var newElem = oldElem.clone(true);
var lastHidden = $('form :hidden:last');
lastHidden.val(newPrefix);
var pat = '=\"' + n[1] + 'input';
newElem.html(newElem.html().replace(new RegExp(pat, 'g'), '=\"' + newPrefix + 'input'));
newElem.appendTo('table');
$('form :hidden:last').val('');
}
function removeItem() {
var rows = $('form tr');
if (rows.length > 2) {
rows[rows.length - 1].html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<html>
<body>
<form autocomplete="off" method="post" action="">
<p>Title:<input type="text" /></p>
<button onclick="addItem(); return false;">Add Item</button>
<button onclick="removeItem(); return false;">Remove Last Item</button>
<table>
<th>Name</th>
<tr>
<td><input type="text" id="input1" name="input1" /></td>
<td><input type="hidden" id="input2" name="input2" /></td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
</body>
</html>

You're using an HTML5 button element. Remember the reason is this button has a default behavior of submit, as stated in the W3 specification as seen here:
W3C HTML5 Button
So you need to specify its type explicitly:
<button type="button">Button</button>
in order to override the default submit type. I just want to point out the reason why this happens.

Set the type on your buttons:
<button type="button" onclick="addItem(); return false;">Add Item</button>
<button type="button" onclick="removeItem(); return false;">Remove Last Item</button>
...that'll keep them from triggering a submit action when an exception occurs in the event handler. Then, fix your removeItem() function so that it doesn't trigger an exception:
function removeItem() {
var rows = $('form tr');
if ( rows.length > 2 ) {
// change: work on filtered jQuery object
rows.filter(":last").html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
Note the change: your original code extracted a HTML element from the jQuery set, and then tried to call a jQuery method on it - this threw an exception, resulting in the default behavior for the button.
FWIW, there's another way you could go with this... Wire up your event handlers using jQuery, and use the preventDefault() method on jQuery's event object to cancel the default behavior up-front:
$(function() // execute once the DOM has loaded
{
// wire up Add Item button click event
$("#AddItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of add logic
});
// wire up Remove Last Item button click event
$("RemoveLastItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of remove last logic
});
});
...
<button type="button" id="AddItem" name="AddItem">Add Item</button>
<button type="button" id="RemoveLastItem" name="RemoveLastItem">Remove Last Item</button>
This technique keeps all of your logic in one place, making it easier to debug... it also allows you to implement a fall-back by changing the type on the buttons back to submit and handling the event server-side - this is known as unobtrusive JavaScript.

Sometime ago I needed something very similar... and I got it.
So what I put here is how I do the tricks to have a form able to be submitted by JavaScript without any validating and execute validation only when the user presses a button (typically a send button).
For the example I will use a minimal form, only with two fields and a submit button.
Remember what is wanted:
From JavaScript it must be able to be submitted without any checking. However, if the user presses such a button, the validation must be done and form sent only if pass the validation.
Normally all would start from something near this (I removed all extra stuff not important):
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="submit" value="Send" onclick="JavaScript:return Validator();" />
</form>
See how form tag has no onsubmit="..." (remember it was a condition not to have it).
The problem is that the form is always submitted, no matter if onclick returns true or false.
If I change type="submit" for type="button", it seems to work but does not. It never sends the form, but that can be done easily.
So finally I used this:
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="button" value="Send" onclick="JavaScript:return Validator();" />
</form>
And on function Validator, where return True; is, I also add a JavaScript submit sentence, something similar to this:
function Validator(){
// ...bla bla bla... the checks
if( ){
document.getElementById('theFormID').submit();
return(true);
}else{
return(false);
}
}
The id="" is just for JavaScript getElementById, the name="" is just for it to appear on POST data.
On such way it works as I need.
I put this just for people that need no onsubmit function on the form, but make some validation when a button is press by user.
Why I need no onsubmit on form tag? Easy, on other JavaScript parts I need to perform a submit but I do not want there to be any validation.
The reason: If user is the one that performs the submit I want and need the validation to be done, but if it is JavaScript sometimes I need to perform the submit while such validations would avoid it.
It may sounds strange, but not when thinking for example: on a Login ... with some restrictions... like not allow to be used PHP sessions and neither cookies are allowed!
So any link must be converted to such form submit, so the login data is not lost.
When no login is yet done, it must also work. So no validation must be performed on links.
But I want to present a message to the user if the user has not entered both fields, user and pass. So if one is missing, the form must not be sent! there is the problem.
See the problem: the form must not be sent when one field is empty only if the user has pressed a button, if it is a JavaScript code it must be able to be sent.
If I do the work on onsubmit on the form tag, I would need to know if it is the user or other JavaScript. Since no parameters can be passed, it is not possible directly, so some people add a variable to tell if validation must be done or not. First thing on validation function is to check that variable value, etc... Too complicated and code does not say what is really wanted.
So the solution is not to have onsubmit on the form tag. Insead put it where it really is needed, on the button.
For the other side, why put onsubmit code since conceptually I do not want onsubmit validation. I really want button validation.
Not only the code is more clear, it is where it must be. Just remember this:
- I do not want JavaScript to validate the form (that must be always done by PHP on the server side)
- I want to show to the user a message telling all fields must not be empty, that needs JavaScript (client side)
So why some people (think or tell me) it must be done on an onsumbit validation? No, conceptually I am not doing a onsumbit validating at client side. I am just doing something on a button get pressed, so why not just let that to be implemented?
Well that code and style does the trick perfectly. On any JavaScript that I need to send the form I just put:
document.getElementById('theFormID').action='./GoToThisPage.php'; // Where to go
document.getElementById('theFormID').submit(); // Send POST data and go there
And that skips validation when I do not need it. It just sends the form and loads a different page, etc.
But if the user clicks the submit button (aka type="button" not type="submit") the validation is done before letting the form be submitted and if not valid not sent.
Well hope this helps others not to try long and complicated code. Just not use onsubmit if not needed, and use onclick. But just remember to change type="submit" to type="button" and please do not forget to do the submit() by JavaScript.

I agree with Shog9, though I might instead use:
<input type = "button" onClick="addItem(); return false;" value="Add Item" />
According to w3schools, the <button> tag has different behavior on different browsers.

You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:
$(document).ready(function () {
$('#BUTTON_ID').click(function(e) {
e.preventDefault();
e.stopPropagation();
e.stopImmediatePropagation();
return false;
});});

$("form").submit(function () { return false; });
that will prevent the button from submitting or you can just change the button type to "button" <input type="button"/> instead of <input type="submit"/>
Which will only work if this button isn't the only button in this form.

Suppose your HTML form has id="form_id"
<form id="form_id">
<!--your HTML code-->
</form>
Add this jQuery snippet to your code to see result,
$("#form_id").submit(function(){
return false;
});

Buttons like <button>Click to do something</button> are submit buttons.
You must add type

This is an html5 error like has been said, you can still have the button as a submit (if you want to cover both javascript and non javascript users) using it like:
<button type="submit" onclick="return false"> Register </button>
This way you will cancel the submit but still do whatever you are doing in jquery or javascript function`s and do the submit for users who dont have javascript.

Just add e.preventDefault(); in your method should prevent your page from submitting forms.
function myFunc(e){
e.preventDefault();
}
According to the MDN Web Docs
The preventDefault () method of the Event interface tells the user
agent that if the event is not explicitly processed, its default
action should not be taken into account as it would normally be. The
event continues to propagate as usual, unless one of its listeners
calls stopPropagation () or stopImmediatePropagation (), either of
which terminates the propagation.

The return false prevents the default behavior. but the return false breaks the bubbling of additional click events. This means if there are any other click bindings after this function gets called, those others do not Consider.
<button id="btnSubmit" type="button">PostData</button>
<Script> $("#btnSubmit").click(function(){
// do stuff
return false;
}); </Script>
Or simply you can put like this
<button type="submit" onclick="return false"> PostData</button>

I am sure that on FF the
removeItem
function encounter a JavaScript error, this not happend on IE
When javascript error appear the "return false" code won't run, making the page to postback

Set your button in normal way and use event.preventDefault like..
<button onclick="myFunc(e)"> Remove </button>
...
...
In function...
function myFunc(e){
e.preventDefault();
}

return false;
You can return false at the end of the function or after the function call.
Just as long as it's the last thing that happens, the form will not submit.

if you have <input />
use it
<input type="button"/>
if you have <button>btn</button>
use it
<button type="button">btn</button>

Here's a simple approach:
$('.mybutton').click(function(){
/* Perform some button action ... */
alert("I don't like it when you press my button!");
/* Then, the most important part ... */
return false;
});

I'm not able to test this right now, but I would think you could use jQuery's preventDefault method.

The following sample code show you how to prevent button click from submitting form.
You may try my sample code:
<form autocomplete="off" method="post" action="">
<p>Title:
<input type="text" />
</p>
<input type="button" onclick="addItem()" value="Add Item">
<input type="button" onclick="removeItem()" value="Remove Last Item">
<table>
<th>Name</th>
<tr>
<td>
<input type="text" id="input1" name="input1" />
</td>
<td>
<input type="hidden" id="input2" name="input2" />
</td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
<script language="javascript">
function addItem() {
return false;
}
function removeItem() {
return false;
}
</script>

The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.
Check out the function removeItem in the javascript part:
The line:
rows[rows.length-1].html('');
doesn't work. Try this instead:
rows.eq(rows.length-1).html('');

https://developer.mozilla.org/pt-BR/docs/Web/API/HTMLFormElement/submit_event
Do your logic on the form onsubmit event
submitter Read only
An HTMLElement object which identifies the button or other element which was invoked to trigger the form being submitted.
onsubmit="(evt) => console.log(evt)"
The event itself will bring along the caller and some usefull info.
Just use evt.preventDefault(); (default submit) evt.stopPropagation(); (submit bubbling) if the caller is a

State is of my react app is not changing after clicking the button [duplicate]

In the following page, with Firefox the remove button submits the form, but the add button does not.
How do I prevent the remove button from submitting the form?
function addItem() {
var v = $('form :hidden:last').attr('name');
var n = /(.*)input/.exec(v);
var newPrefix;
if (n[1].length == 0) {
newPrefix = '1';
} else {
newPrefix = parseInt(n[1]) + 1;
}
var oldElem = $('form tr:last');
var newElem = oldElem.clone(true);
var lastHidden = $('form :hidden:last');
lastHidden.val(newPrefix);
var pat = '=\"' + n[1] + 'input';
newElem.html(newElem.html().replace(new RegExp(pat, 'g'), '=\"' + newPrefix + 'input'));
newElem.appendTo('table');
$('form :hidden:last').val('');
}
function removeItem() {
var rows = $('form tr');
if (rows.length > 2) {
rows[rows.length - 1].html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<html>
<body>
<form autocomplete="off" method="post" action="">
<p>Title:<input type="text" /></p>
<button onclick="addItem(); return false;">Add Item</button>
<button onclick="removeItem(); return false;">Remove Last Item</button>
<table>
<th>Name</th>
<tr>
<td><input type="text" id="input1" name="input1" /></td>
<td><input type="hidden" id="input2" name="input2" /></td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
</body>
</html>

You're using an HTML5 button element. Remember the reason is this button has a default behavior of submit, as stated in the W3 specification as seen here:
W3C HTML5 Button
So you need to specify its type explicitly:
<button type="button">Button</button>
in order to override the default submit type. I just want to point out the reason why this happens.

Set the type on your buttons:
<button type="button" onclick="addItem(); return false;">Add Item</button>
<button type="button" onclick="removeItem(); return false;">Remove Last Item</button>
...that'll keep them from triggering a submit action when an exception occurs in the event handler. Then, fix your removeItem() function so that it doesn't trigger an exception:
function removeItem() {
var rows = $('form tr');
if ( rows.length > 2 ) {
// change: work on filtered jQuery object
rows.filter(":last").html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
Note the change: your original code extracted a HTML element from the jQuery set, and then tried to call a jQuery method on it - this threw an exception, resulting in the default behavior for the button.
FWIW, there's another way you could go with this... Wire up your event handlers using jQuery, and use the preventDefault() method on jQuery's event object to cancel the default behavior up-front:
$(function() // execute once the DOM has loaded
{
// wire up Add Item button click event
$("#AddItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of add logic
});
// wire up Remove Last Item button click event
$("RemoveLastItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of remove last logic
});
});
...
<button type="button" id="AddItem" name="AddItem">Add Item</button>
<button type="button" id="RemoveLastItem" name="RemoveLastItem">Remove Last Item</button>
This technique keeps all of your logic in one place, making it easier to debug... it also allows you to implement a fall-back by changing the type on the buttons back to submit and handling the event server-side - this is known as unobtrusive JavaScript.

Sometime ago I needed something very similar... and I got it.
So what I put here is how I do the tricks to have a form able to be submitted by JavaScript without any validating and execute validation only when the user presses a button (typically a send button).
For the example I will use a minimal form, only with two fields and a submit button.
Remember what is wanted:
From JavaScript it must be able to be submitted without any checking. However, if the user presses such a button, the validation must be done and form sent only if pass the validation.
Normally all would start from something near this (I removed all extra stuff not important):
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="submit" value="Send" onclick="JavaScript:return Validator();" />
</form>
See how form tag has no onsubmit="..." (remember it was a condition not to have it).
The problem is that the form is always submitted, no matter if onclick returns true or false.
If I change type="submit" for type="button", it seems to work but does not. It never sends the form, but that can be done easily.
So finally I used this:
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="button" value="Send" onclick="JavaScript:return Validator();" />
</form>
And on function Validator, where return True; is, I also add a JavaScript submit sentence, something similar to this:
function Validator(){
// ...bla bla bla... the checks
if( ){
document.getElementById('theFormID').submit();
return(true);
}else{
return(false);
}
}
The id="" is just for JavaScript getElementById, the name="" is just for it to appear on POST data.
On such way it works as I need.
I put this just for people that need no onsubmit function on the form, but make some validation when a button is press by user.
Why I need no onsubmit on form tag? Easy, on other JavaScript parts I need to perform a submit but I do not want there to be any validation.
The reason: If user is the one that performs the submit I want and need the validation to be done, but if it is JavaScript sometimes I need to perform the submit while such validations would avoid it.
It may sounds strange, but not when thinking for example: on a Login ... with some restrictions... like not allow to be used PHP sessions and neither cookies are allowed!
So any link must be converted to such form submit, so the login data is not lost.
When no login is yet done, it must also work. So no validation must be performed on links.
But I want to present a message to the user if the user has not entered both fields, user and pass. So if one is missing, the form must not be sent! there is the problem.
See the problem: the form must not be sent when one field is empty only if the user has pressed a button, if it is a JavaScript code it must be able to be sent.
If I do the work on onsubmit on the form tag, I would need to know if it is the user or other JavaScript. Since no parameters can be passed, it is not possible directly, so some people add a variable to tell if validation must be done or not. First thing on validation function is to check that variable value, etc... Too complicated and code does not say what is really wanted.
So the solution is not to have onsubmit on the form tag. Insead put it where it really is needed, on the button.
For the other side, why put onsubmit code since conceptually I do not want onsubmit validation. I really want button validation.
Not only the code is more clear, it is where it must be. Just remember this:
- I do not want JavaScript to validate the form (that must be always done by PHP on the server side)
- I want to show to the user a message telling all fields must not be empty, that needs JavaScript (client side)
So why some people (think or tell me) it must be done on an onsumbit validation? No, conceptually I am not doing a onsumbit validating at client side. I am just doing something on a button get pressed, so why not just let that to be implemented?
Well that code and style does the trick perfectly. On any JavaScript that I need to send the form I just put:
document.getElementById('theFormID').action='./GoToThisPage.php'; // Where to go
document.getElementById('theFormID').submit(); // Send POST data and go there
And that skips validation when I do not need it. It just sends the form and loads a different page, etc.
But if the user clicks the submit button (aka type="button" not type="submit") the validation is done before letting the form be submitted and if not valid not sent.
Well hope this helps others not to try long and complicated code. Just not use onsubmit if not needed, and use onclick. But just remember to change type="submit" to type="button" and please do not forget to do the submit() by JavaScript.

I agree with Shog9, though I might instead use:
<input type = "button" onClick="addItem(); return false;" value="Add Item" />
According to w3schools, the <button> tag has different behavior on different browsers.

You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:
$(document).ready(function () {
$('#BUTTON_ID').click(function(e) {
e.preventDefault();
e.stopPropagation();
e.stopImmediatePropagation();
return false;
});});

$("form").submit(function () { return false; });
that will prevent the button from submitting or you can just change the button type to "button" <input type="button"/> instead of <input type="submit"/>
Which will only work if this button isn't the only button in this form.

Suppose your HTML form has id="form_id"
<form id="form_id">
<!--your HTML code-->
</form>
Add this jQuery snippet to your code to see result,
$("#form_id").submit(function(){
return false;
});

Buttons like <button>Click to do something</button> are submit buttons.
You must add type

This is an html5 error like has been said, you can still have the button as a submit (if you want to cover both javascript and non javascript users) using it like:
<button type="submit" onclick="return false"> Register </button>
This way you will cancel the submit but still do whatever you are doing in jquery or javascript function`s and do the submit for users who dont have javascript.

Just add e.preventDefault(); in your method should prevent your page from submitting forms.
function myFunc(e){
e.preventDefault();
}
According to the MDN Web Docs
The preventDefault () method of the Event interface tells the user
agent that if the event is not explicitly processed, its default
action should not be taken into account as it would normally be. The
event continues to propagate as usual, unless one of its listeners
calls stopPropagation () or stopImmediatePropagation (), either of
which terminates the propagation.

The return false prevents the default behavior. but the return false breaks the bubbling of additional click events. This means if there are any other click bindings after this function gets called, those others do not Consider.
<button id="btnSubmit" type="button">PostData</button>
<Script> $("#btnSubmit").click(function(){
// do stuff
return false;
}); </Script>
Or simply you can put like this
<button type="submit" onclick="return false"> PostData</button>

I am sure that on FF the
removeItem
function encounter a JavaScript error, this not happend on IE
When javascript error appear the "return false" code won't run, making the page to postback

Set your button in normal way and use event.preventDefault like..
<button onclick="myFunc(e)"> Remove </button>
...
...
In function...
function myFunc(e){
e.preventDefault();
}

return false;
You can return false at the end of the function or after the function call.
Just as long as it's the last thing that happens, the form will not submit.

if you have <input />
use it
<input type="button"/>
if you have <button>btn</button>
use it
<button type="button">btn</button>

Here's a simple approach:
$('.mybutton').click(function(){
/* Perform some button action ... */
alert("I don't like it when you press my button!");
/* Then, the most important part ... */
return false;
});

I'm not able to test this right now, but I would think you could use jQuery's preventDefault method.

The following sample code show you how to prevent button click from submitting form.
You may try my sample code:
<form autocomplete="off" method="post" action="">
<p>Title:
<input type="text" />
</p>
<input type="button" onclick="addItem()" value="Add Item">
<input type="button" onclick="removeItem()" value="Remove Last Item">
<table>
<th>Name</th>
<tr>
<td>
<input type="text" id="input1" name="input1" />
</td>
<td>
<input type="hidden" id="input2" name="input2" />
</td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
<script language="javascript">
function addItem() {
return false;
}
function removeItem() {
return false;
}
</script>

The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.
Check out the function removeItem in the javascript part:
The line:
rows[rows.length-1].html('');
doesn't work. Try this instead:
rows.eq(rows.length-1).html('');

https://developer.mozilla.org/pt-BR/docs/Web/API/HTMLFormElement/submit_event
Do your logic on the form onsubmit event
submitter Read only
An HTMLElement object which identifies the button or other element which was invoked to trigger the form being submitted.
onsubmit="(evt) => console.log(evt)"
The event itself will bring along the caller and some usefull info.
Just use evt.preventDefault(); (default submit) evt.stopPropagation(); (submit bubbling) if the caller is a

Calculations with JavaScript without submitting the form [duplicate]

In the following page, with Firefox the remove button submits the form, but the add button does not.
How do I prevent the remove button from submitting the form?
function addItem() {
var v = $('form :hidden:last').attr('name');
var n = /(.*)input/.exec(v);
var newPrefix;
if (n[1].length == 0) {
newPrefix = '1';
} else {
newPrefix = parseInt(n[1]) + 1;
}
var oldElem = $('form tr:last');
var newElem = oldElem.clone(true);
var lastHidden = $('form :hidden:last');
lastHidden.val(newPrefix);
var pat = '=\"' + n[1] + 'input';
newElem.html(newElem.html().replace(new RegExp(pat, 'g'), '=\"' + newPrefix + 'input'));
newElem.appendTo('table');
$('form :hidden:last').val('');
}
function removeItem() {
var rows = $('form tr');
if (rows.length > 2) {
rows[rows.length - 1].html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<html>
<body>
<form autocomplete="off" method="post" action="">
<p>Title:<input type="text" /></p>
<button onclick="addItem(); return false;">Add Item</button>
<button onclick="removeItem(); return false;">Remove Last Item</button>
<table>
<th>Name</th>
<tr>
<td><input type="text" id="input1" name="input1" /></td>
<td><input type="hidden" id="input2" name="input2" /></td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
</body>
</html>

You're using an HTML5 button element. Remember the reason is this button has a default behavior of submit, as stated in the W3 specification as seen here:
W3C HTML5 Button
So you need to specify its type explicitly:
<button type="button">Button</button>
in order to override the default submit type. I just want to point out the reason why this happens.

Set the type on your buttons:
<button type="button" onclick="addItem(); return false;">Add Item</button>
<button type="button" onclick="removeItem(); return false;">Remove Last Item</button>
...that'll keep them from triggering a submit action when an exception occurs in the event handler. Then, fix your removeItem() function so that it doesn't trigger an exception:
function removeItem() {
var rows = $('form tr');
if ( rows.length > 2 ) {
// change: work on filtered jQuery object
rows.filter(":last").html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
Note the change: your original code extracted a HTML element from the jQuery set, and then tried to call a jQuery method on it - this threw an exception, resulting in the default behavior for the button.
FWIW, there's another way you could go with this... Wire up your event handlers using jQuery, and use the preventDefault() method on jQuery's event object to cancel the default behavior up-front:
$(function() // execute once the DOM has loaded
{
// wire up Add Item button click event
$("#AddItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of add logic
});
// wire up Remove Last Item button click event
$("RemoveLastItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of remove last logic
});
});
...
<button type="button" id="AddItem" name="AddItem">Add Item</button>
<button type="button" id="RemoveLastItem" name="RemoveLastItem">Remove Last Item</button>
This technique keeps all of your logic in one place, making it easier to debug... it also allows you to implement a fall-back by changing the type on the buttons back to submit and handling the event server-side - this is known as unobtrusive JavaScript.

Sometime ago I needed something very similar... and I got it.
So what I put here is how I do the tricks to have a form able to be submitted by JavaScript without any validating and execute validation only when the user presses a button (typically a send button).
For the example I will use a minimal form, only with two fields and a submit button.
Remember what is wanted:
From JavaScript it must be able to be submitted without any checking. However, if the user presses such a button, the validation must be done and form sent only if pass the validation.
Normally all would start from something near this (I removed all extra stuff not important):
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="submit" value="Send" onclick="JavaScript:return Validator();" />
</form>
See how form tag has no onsubmit="..." (remember it was a condition not to have it).
The problem is that the form is always submitted, no matter if onclick returns true or false.
If I change type="submit" for type="button", it seems to work but does not. It never sends the form, but that can be done easily.
So finally I used this:
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="button" value="Send" onclick="JavaScript:return Validator();" />
</form>
And on function Validator, where return True; is, I also add a JavaScript submit sentence, something similar to this:
function Validator(){
// ...bla bla bla... the checks
if( ){
document.getElementById('theFormID').submit();
return(true);
}else{
return(false);
}
}
The id="" is just for JavaScript getElementById, the name="" is just for it to appear on POST data.
On such way it works as I need.
I put this just for people that need no onsubmit function on the form, but make some validation when a button is press by user.
Why I need no onsubmit on form tag? Easy, on other JavaScript parts I need to perform a submit but I do not want there to be any validation.
The reason: If user is the one that performs the submit I want and need the validation to be done, but if it is JavaScript sometimes I need to perform the submit while such validations would avoid it.
It may sounds strange, but not when thinking for example: on a Login ... with some restrictions... like not allow to be used PHP sessions and neither cookies are allowed!
So any link must be converted to such form submit, so the login data is not lost.
When no login is yet done, it must also work. So no validation must be performed on links.
But I want to present a message to the user if the user has not entered both fields, user and pass. So if one is missing, the form must not be sent! there is the problem.
See the problem: the form must not be sent when one field is empty only if the user has pressed a button, if it is a JavaScript code it must be able to be sent.
If I do the work on onsubmit on the form tag, I would need to know if it is the user or other JavaScript. Since no parameters can be passed, it is not possible directly, so some people add a variable to tell if validation must be done or not. First thing on validation function is to check that variable value, etc... Too complicated and code does not say what is really wanted.
So the solution is not to have onsubmit on the form tag. Insead put it where it really is needed, on the button.
For the other side, why put onsubmit code since conceptually I do not want onsubmit validation. I really want button validation.
Not only the code is more clear, it is where it must be. Just remember this:
- I do not want JavaScript to validate the form (that must be always done by PHP on the server side)
- I want to show to the user a message telling all fields must not be empty, that needs JavaScript (client side)
So why some people (think or tell me) it must be done on an onsumbit validation? No, conceptually I am not doing a onsumbit validating at client side. I am just doing something on a button get pressed, so why not just let that to be implemented?
Well that code and style does the trick perfectly. On any JavaScript that I need to send the form I just put:
document.getElementById('theFormID').action='./GoToThisPage.php'; // Where to go
document.getElementById('theFormID').submit(); // Send POST data and go there
And that skips validation when I do not need it. It just sends the form and loads a different page, etc.
But if the user clicks the submit button (aka type="button" not type="submit") the validation is done before letting the form be submitted and if not valid not sent.
Well hope this helps others not to try long and complicated code. Just not use onsubmit if not needed, and use onclick. But just remember to change type="submit" to type="button" and please do not forget to do the submit() by JavaScript.

I agree with Shog9, though I might instead use:
<input type = "button" onClick="addItem(); return false;" value="Add Item" />
According to w3schools, the <button> tag has different behavior on different browsers.

You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:
$(document).ready(function () {
$('#BUTTON_ID').click(function(e) {
e.preventDefault();
e.stopPropagation();
e.stopImmediatePropagation();
return false;
});});

$("form").submit(function () { return false; });
that will prevent the button from submitting or you can just change the button type to "button" <input type="button"/> instead of <input type="submit"/>
Which will only work if this button isn't the only button in this form.

Suppose your HTML form has id="form_id"
<form id="form_id">
<!--your HTML code-->
</form>
Add this jQuery snippet to your code to see result,
$("#form_id").submit(function(){
return false;
});

Buttons like <button>Click to do something</button> are submit buttons.
You must add type

This is an html5 error like has been said, you can still have the button as a submit (if you want to cover both javascript and non javascript users) using it like:
<button type="submit" onclick="return false"> Register </button>
This way you will cancel the submit but still do whatever you are doing in jquery or javascript function`s and do the submit for users who dont have javascript.

Just add e.preventDefault(); in your method should prevent your page from submitting forms.
function myFunc(e){
e.preventDefault();
}
According to the MDN Web Docs
The preventDefault () method of the Event interface tells the user
agent that if the event is not explicitly processed, its default
action should not be taken into account as it would normally be. The
event continues to propagate as usual, unless one of its listeners
calls stopPropagation () or stopImmediatePropagation (), either of
which terminates the propagation.

The return false prevents the default behavior. but the return false breaks the bubbling of additional click events. This means if there are any other click bindings after this function gets called, those others do not Consider.
<button id="btnSubmit" type="button">PostData</button>
<Script> $("#btnSubmit").click(function(){
// do stuff
return false;
}); </Script>
Or simply you can put like this
<button type="submit" onclick="return false"> PostData</button>

I am sure that on FF the
removeItem
function encounter a JavaScript error, this not happend on IE
When javascript error appear the "return false" code won't run, making the page to postback

Set your button in normal way and use event.preventDefault like..
<button onclick="myFunc(e)"> Remove </button>
...
...
In function...
function myFunc(e){
e.preventDefault();
}

return false;
You can return false at the end of the function or after the function call.
Just as long as it's the last thing that happens, the form will not submit.

if you have <input />
use it
<input type="button"/>
if you have <button>btn</button>
use it
<button type="button">btn</button>

Here's a simple approach:
$('.mybutton').click(function(){
/* Perform some button action ... */
alert("I don't like it when you press my button!");
/* Then, the most important part ... */
return false;
});

I'm not able to test this right now, but I would think you could use jQuery's preventDefault method.

The following sample code show you how to prevent button click from submitting form.
You may try my sample code:
<form autocomplete="off" method="post" action="">
<p>Title:
<input type="text" />
</p>
<input type="button" onclick="addItem()" value="Add Item">
<input type="button" onclick="removeItem()" value="Remove Last Item">
<table>
<th>Name</th>
<tr>
<td>
<input type="text" id="input1" name="input1" />
</td>
<td>
<input type="hidden" id="input2" name="input2" />
</td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
<script language="javascript">
function addItem() {
return false;
}
function removeItem() {
return false;
}
</script>

The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.
Check out the function removeItem in the javascript part:
The line:
rows[rows.length-1].html('');
doesn't work. Try this instead:
rows.eq(rows.length-1).html('');

https://developer.mozilla.org/pt-BR/docs/Web/API/HTMLFormElement/submit_event
Do your logic on the form onsubmit event
submitter Read only
An HTMLElement object which identifies the button or other element which was invoked to trigger the form being submitted.
onsubmit="(evt) => console.log(evt)"
The event itself will bring along the caller and some usefull info.
Just use evt.preventDefault(); (default submit) evt.stopPropagation(); (submit bubbling) if the caller is a

fetch post with log-in form returns server error 400 with invalid credentials [duplicate]

I have an issue while using buttons inside form. I want that button to call function. It does, but with unwanted result that it refresh the page.
My simple code goes like this
<form method="POST">
<button name="data" onclick="getData()">Click</button>
</form>
On clicking the button, the function gets called with page refreshed, which resets all my previous request which affects the current page which was result of the previous request.
What should I do to prevent the page refresh?

Add type="button" to the button.
<button name="data" type="button" onclick="getData()">Click</button>
The default value of type for a button is submit, which self posts the form in your case and makes it look like a refresh.

Let getData() return false. This will fix it.
<form method="POST">
<button name="data" onclick="return getData()">Click</button>
</form>

All you need to do is put a type tag and make the type button.
<button id="btnId" type="button">Hide/Show</button>
That solves the issue

The problem is that it triggers the form submission. If you make the getData function return false then it should stop the form from submitting.
Alternatively, you could also use the preventDefault method of the event object:
function getData(e) {
e.preventDefault();
}

HTML
<form onsubmit="return false;" id="myForm">
</form>
jQuery
$('#myForm').submit(function() {
doSomething();
});

<form method="POST">
<button name="data" onclick="getData()">Click</button>
</form>
instead of using button tag, use input tag. Like this,
<form method="POST">
<input type = "button" name="data" onclick="getData()" value="Click">
</form>

If your button is default "button" make sure you explicity set the type attribute, otherwise the WebForm will treat it as submit by default.
if you use js do like this
<form method="POST">
<button name="data" type="button" id="btnData" onclick="getData()">Click</button>
</form>
**If you use jquery use like this**
<form method="POST">
<button name="data" type="button" id="btnData">Click</button>
</form>
$('#btnData').click(function(e){
e.preventDefault();
// Code goes here
getData(); // your onclick function call here
});

A javascript method to disable the button itself
document.getElementById("ID NAME").disabled = true;
Once all form fields have satisfied your criteria, you can re-enable the button
Using a Jquery will be something like this
$( "#ID NAME" ).prop( "disabled", true);

This one is the best solution:
<form method="post">
<button type="button" name="data" onclick="getData()">Click Me</button>
</form>
Note: My code is very simple.

For any reason in Firefox even though I have return false; and myform.preventDefault(); in the function, it refreshes the page after function runs. And I don't know if this is a good practice, but it works for me, I insert javascript:this.preventDefault(); in the action attribute .
As I said, I tried all the other suggestions and they work fine in all browsers but Firefox, if you have the same issue, try adding the prevent event in the action attribute either javascript:return false; or javascript:this.preventDefault();. Do not try with javascript:void(0); which will break your code. Don't ask me why :-).
I don't think this is an elegant way to do it, but in my case I had no other choice.
Update:
If you received an error... after ajax is processed, then remove the attribute action and in the onsubmit attribute, execute your function followed by the false return:
onsubmit="functionToRun(); return false;"
I don't know why all this trouble with Firefox, but hope this works.

Return function is not working in all the cases.
I tried this:
<button id="Reset" class="Button-class" onclick="return Reset()">Show result</button>
It didnt work for me.
I tried to return false inside the function and it worked for me.
function Reset()
{
.
.
.
return false;
}

I was facing the same problem. The problem is with the onclick function. There should not be any problem with the function getData. It worked by making the onclick function return false.
<form method="POST">
<button name="data" onclick="getData(); return false">Click</button>
</form>

I updated on #JNDPNT answer, this way the function (getData()) doesn't have to return false;
<form method="POST">
<button name="data" onclick="getData(); return false;">Click</button>
</form>

A simple issue I found is that if the function that you're trying to call is called submit, the form will be submitted either way.
You will need to rename the function for the page to not be reloaded

Add e.preventDefault(); in the starting of the function to be called when the button is clicked
Example:
const signUp = (e) => {
e.preventDefault()
try {
} catch (error) {
console.log(error.message)
}
}
The button code:
<input
type='submit'
name='submit-btn'
id='submit-btn'
value='Sign Up'
onClick={signUp}
/>

You can use ajax and jquery to solve this problem:
<script>
function getData() {
$.ajax({
url : "/urlpattern",
type : "post",
success : function(data) {
alert("success");
}
});
}
</script>
<form method="POST">
<button name="data" type="button" onclick="getData()">Click</button>
</form>

Button inside form automatically acting as submit [duplicate]

In the following page, with Firefox the remove button submits the form, but the add button does not.
How do I prevent the remove button from submitting the form?
function addItem() {
var v = $('form :hidden:last').attr('name');
var n = /(.*)input/.exec(v);
var newPrefix;
if (n[1].length == 0) {
newPrefix = '1';
} else {
newPrefix = parseInt(n[1]) + 1;
}
var oldElem = $('form tr:last');
var newElem = oldElem.clone(true);
var lastHidden = $('form :hidden:last');
lastHidden.val(newPrefix);
var pat = '=\"' + n[1] + 'input';
newElem.html(newElem.html().replace(new RegExp(pat, 'g'), '=\"' + newPrefix + 'input'));
newElem.appendTo('table');
$('form :hidden:last').val('');
}
function removeItem() {
var rows = $('form tr');
if (rows.length > 2) {
rows[rows.length - 1].html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<html>
<body>
<form autocomplete="off" method="post" action="">
<p>Title:<input type="text" /></p>
<button onclick="addItem(); return false;">Add Item</button>
<button onclick="removeItem(); return false;">Remove Last Item</button>
<table>
<th>Name</th>
<tr>
<td><input type="text" id="input1" name="input1" /></td>
<td><input type="hidden" id="input2" name="input2" /></td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
</body>
</html>

You're using an HTML5 button element. Remember the reason is this button has a default behavior of submit, as stated in the W3 specification as seen here:
W3C HTML5 Button
So you need to specify its type explicitly:
<button type="button">Button</button>
in order to override the default submit type. I just want to point out the reason why this happens.

Set the type on your buttons:
<button type="button" onclick="addItem(); return false;">Add Item</button>
<button type="button" onclick="removeItem(); return false;">Remove Last Item</button>
...that'll keep them from triggering a submit action when an exception occurs in the event handler. Then, fix your removeItem() function so that it doesn't trigger an exception:
function removeItem() {
var rows = $('form tr');
if ( rows.length > 2 ) {
// change: work on filtered jQuery object
rows.filter(":last").html('');
$('form :hidden:last').val('');
} else {
alert('Cannot remove any more rows');
}
}
Note the change: your original code extracted a HTML element from the jQuery set, and then tried to call a jQuery method on it - this threw an exception, resulting in the default behavior for the button.
FWIW, there's another way you could go with this... Wire up your event handlers using jQuery, and use the preventDefault() method on jQuery's event object to cancel the default behavior up-front:
$(function() // execute once the DOM has loaded
{
// wire up Add Item button click event
$("#AddItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of add logic
});
// wire up Remove Last Item button click event
$("RemoveLastItem").click(function(event)
{
event.preventDefault(); // cancel default behavior
//... rest of remove last logic
});
});
...
<button type="button" id="AddItem" name="AddItem">Add Item</button>
<button type="button" id="RemoveLastItem" name="RemoveLastItem">Remove Last Item</button>
This technique keeps all of your logic in one place, making it easier to debug... it also allows you to implement a fall-back by changing the type on the buttons back to submit and handling the event server-side - this is known as unobtrusive JavaScript.

Sometime ago I needed something very similar... and I got it.
So what I put here is how I do the tricks to have a form able to be submitted by JavaScript without any validating and execute validation only when the user presses a button (typically a send button).
For the example I will use a minimal form, only with two fields and a submit button.
Remember what is wanted:
From JavaScript it must be able to be submitted without any checking. However, if the user presses such a button, the validation must be done and form sent only if pass the validation.
Normally all would start from something near this (I removed all extra stuff not important):
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="submit" value="Send" onclick="JavaScript:return Validator();" />
</form>
See how form tag has no onsubmit="..." (remember it was a condition not to have it).
The problem is that the form is always submitted, no matter if onclick returns true or false.
If I change type="submit" for type="button", it seems to work but does not. It never sends the form, but that can be done easily.
So finally I used this:
<form method="post" id="theFormID" name="theFormID" action="">
<input type="text" id="Field1" name="Field1" />
<input type="text" id="Field2" name="Field2" />
<input type="button" value="Send" onclick="JavaScript:return Validator();" />
</form>
And on function Validator, where return True; is, I also add a JavaScript submit sentence, something similar to this:
function Validator(){
// ...bla bla bla... the checks
if( ){
document.getElementById('theFormID').submit();
return(true);
}else{
return(false);
}
}
The id="" is just for JavaScript getElementById, the name="" is just for it to appear on POST data.
On such way it works as I need.
I put this just for people that need no onsubmit function on the form, but make some validation when a button is press by user.
Why I need no onsubmit on form tag? Easy, on other JavaScript parts I need to perform a submit but I do not want there to be any validation.
The reason: If user is the one that performs the submit I want and need the validation to be done, but if it is JavaScript sometimes I need to perform the submit while such validations would avoid it.
It may sounds strange, but not when thinking for example: on a Login ... with some restrictions... like not allow to be used PHP sessions and neither cookies are allowed!
So any link must be converted to such form submit, so the login data is not lost.
When no login is yet done, it must also work. So no validation must be performed on links.
But I want to present a message to the user if the user has not entered both fields, user and pass. So if one is missing, the form must not be sent! there is the problem.
See the problem: the form must not be sent when one field is empty only if the user has pressed a button, if it is a JavaScript code it must be able to be sent.
If I do the work on onsubmit on the form tag, I would need to know if it is the user or other JavaScript. Since no parameters can be passed, it is not possible directly, so some people add a variable to tell if validation must be done or not. First thing on validation function is to check that variable value, etc... Too complicated and code does not say what is really wanted.
So the solution is not to have onsubmit on the form tag. Insead put it where it really is needed, on the button.
For the other side, why put onsubmit code since conceptually I do not want onsubmit validation. I really want button validation.
Not only the code is more clear, it is where it must be. Just remember this:
- I do not want JavaScript to validate the form (that must be always done by PHP on the server side)
- I want to show to the user a message telling all fields must not be empty, that needs JavaScript (client side)
So why some people (think or tell me) it must be done on an onsumbit validation? No, conceptually I am not doing a onsumbit validating at client side. I am just doing something on a button get pressed, so why not just let that to be implemented?
Well that code and style does the trick perfectly. On any JavaScript that I need to send the form I just put:
document.getElementById('theFormID').action='./GoToThisPage.php'; // Where to go
document.getElementById('theFormID').submit(); // Send POST data and go there
And that skips validation when I do not need it. It just sends the form and loads a different page, etc.
But if the user clicks the submit button (aka type="button" not type="submit") the validation is done before letting the form be submitted and if not valid not sent.
Well hope this helps others not to try long and complicated code. Just not use onsubmit if not needed, and use onclick. But just remember to change type="submit" to type="button" and please do not forget to do the submit() by JavaScript.

I agree with Shog9, though I might instead use:
<input type = "button" onClick="addItem(); return false;" value="Add Item" />
According to w3schools, the <button> tag has different behavior on different browsers.

You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:
$(document).ready(function () {
$('#BUTTON_ID').click(function(e) {
e.preventDefault();
e.stopPropagation();
e.stopImmediatePropagation();
return false;
});});

$("form").submit(function () { return false; });
that will prevent the button from submitting or you can just change the button type to "button" <input type="button"/> instead of <input type="submit"/>
Which will only work if this button isn't the only button in this form.

Suppose your HTML form has id="form_id"
<form id="form_id">
<!--your HTML code-->
</form>
Add this jQuery snippet to your code to see result,
$("#form_id").submit(function(){
return false;
});

Buttons like <button>Click to do something</button> are submit buttons.
You must add type

This is an html5 error like has been said, you can still have the button as a submit (if you want to cover both javascript and non javascript users) using it like:
<button type="submit" onclick="return false"> Register </button>
This way you will cancel the submit but still do whatever you are doing in jquery or javascript function`s and do the submit for users who dont have javascript.

Just add e.preventDefault(); in your method should prevent your page from submitting forms.
function myFunc(e){
e.preventDefault();
}
According to the MDN Web Docs
The preventDefault () method of the Event interface tells the user
agent that if the event is not explicitly processed, its default
action should not be taken into account as it would normally be. The
event continues to propagate as usual, unless one of its listeners
calls stopPropagation () or stopImmediatePropagation (), either of
which terminates the propagation.

The return false prevents the default behavior. but the return false breaks the bubbling of additional click events. This means if there are any other click bindings after this function gets called, those others do not Consider.
<button id="btnSubmit" type="button">PostData</button>
<Script> $("#btnSubmit").click(function(){
// do stuff
return false;
}); </Script>
Or simply you can put like this
<button type="submit" onclick="return false"> PostData</button>

I am sure that on FF the
removeItem
function encounter a JavaScript error, this not happend on IE
When javascript error appear the "return false" code won't run, making the page to postback

Set your button in normal way and use event.preventDefault like..
<button onclick="myFunc(e)"> Remove </button>
...
...
In function...
function myFunc(e){
e.preventDefault();
}

return false;
You can return false at the end of the function or after the function call.
Just as long as it's the last thing that happens, the form will not submit.

if you have <input />
use it
<input type="button"/>
if you have <button>btn</button>
use it
<button type="button">btn</button>

Here's a simple approach:
$('.mybutton').click(function(){
/* Perform some button action ... */
alert("I don't like it when you press my button!");
/* Then, the most important part ... */
return false;
});

I'm not able to test this right now, but I would think you could use jQuery's preventDefault method.

The following sample code show you how to prevent button click from submitting form.
You may try my sample code:
<form autocomplete="off" method="post" action="">
<p>Title:
<input type="text" />
</p>
<input type="button" onclick="addItem()" value="Add Item">
<input type="button" onclick="removeItem()" value="Remove Last Item">
<table>
<th>Name</th>
<tr>
<td>
<input type="text" id="input1" name="input1" />
</td>
<td>
<input type="hidden" id="input2" name="input2" />
</td>
</tr>
</table>
<input id="submit" type="submit" name="submit" value="Submit">
</form>
<script language="javascript">
function addItem() {
return false;
}
function removeItem() {
return false;
}
</script>

The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.
Check out the function removeItem in the javascript part:
The line:
rows[rows.length-1].html('');
doesn't work. Try this instead:
rows.eq(rows.length-1).html('');

https://developer.mozilla.org/pt-BR/docs/Web/API/HTMLFormElement/submit_event
Do your logic on the form onsubmit event
submitter Read only
An HTMLElement object which identifies the button or other element which was invoked to trigger the form being submitted.
onsubmit="(evt) => console.log(evt)"
The event itself will bring along the caller and some usefull info.
Just use evt.preventDefault(); (default submit) evt.stopPropagation(); (submit bubbling) if the caller is a

Develop Reference

JavaScript is the programming language of the Web.

Submit <button> not submitted with javascript disable - javascript

If <button type="submit"> tag is not inside <form></form> there is nothing to submit. <button type="submit"> submits only it's parent <form>

Try to submit the form with Javascript. function disableButton(btn) { document.getElementById(btn.id).disabled = true; document.getElementById('formId').submit(); alert("Button has been disabled."); }

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