Develop Reference

Avoid multiple form submit in html

I'm facing a sort of dummy problem.
On my site there is an order form (simple html form) and I noticed that I get double commands from time to time.
I realized that if I clicked repeatedly few times the submit button (before the action page is loaded) I got as many commands as I have clicked.
So I wonder if there are simple solution to make form submission asyncronous?
Thanks
P.S. I added JQuery UI dialog on submit "wait please..." but I get still double commands.
UPDATE
As GeoffAtkins proposed I will:
disable submit after dialog is shown
make use of unique form's token (as it is already added by Symfony) Do not use Symfony token as unique form token as it is always the same for current session. Use just random or something like that.

I would consider doing this (jQuery since you said you used that)
$(function() {
$("#formId").on("submit",function() {
$("#submitBut").hide();
$("#pleaseWait").show();
});
});
if you submit the form and reload the page.
If you Ajax the order, then do
$(function() {
$("#formId").on("submit",function(e) {
e.preventDefault();
var $theForm = $(this);
$("#submitBut").hide();
$("#pleaseWait").show();
$.post($(this).attr("action"),$(this).serialize(),function() {
$theForm.reset();
$("#submitBut").show(); // assuming you want the user to order more stuff
$("#pleaseWait").hide();
});
});
});
NOTE that disabling the submit button on click of the submit button may stop the submission all together (at least in Chrome): https://jsfiddle.net/mplungjan/xc6uc46m/

Just disable the button on click, something like:
$("#my-button-id").on("click", function() {
$(this).attr("disabled", "disabled");
});

var bool = true;
function onclick()
{
if(bool)
{
//do stuff
bool = false;
}
else
{
//ignore
}
}

You could disable the button on the form when it is clicked, and then continue to perform the action. You would probably change the text to say "loading..." or some such.
You may also want to re-enable the button on fail or complete of the ajax request.
I've done this many times similar to this: https://stackoverflow.com/a/19220576/89211

Using preventDefault

I've been looking at some code posted by someone and I can't make sense of why he used preventDefault.
var $windows = $('#tgx-window,#tgs-window,#tgm-window,#tgl-window'), $buttons = $('#tgx-button,#tgs-button,#tgm-button,#tgl-button');
$windows.hide();
$buttons.on('click', function(e) {
var $id;
e.preventDefault();
$buttons.removeClass('closebutton');
$id = $('#' + this.id.split('-')[0] + '-window');// Get window id
$windows.slideUp();
if(! $id.is(':visible') ) {
$id.slideDown();
$(this).addClass('closebutton');
}
});
It seems to behave exactly the same with or without it. My best guess so far is that it's common practice to use preventDefault/return false in function bodies.
My question is why he used that method at all?
Oh, yeah. I'm new to JavaScript.
http://jsfiddle.net/62NPt/53/

From the docs:
If this method is called, the default action of the event will not be
triggered.
So if your button is an input submit button for example, the event.preventDefault() will prevent the default behaviour of your button and prevent your form from submitting and reload the page. This is normally helpful when you want to apply AJAX call.

If the button is of type submit and in case of anchor if you use preventDefault() the default action of the event will not be triggered.
If you dont want to stop default action of element then it does not make any difference.

How to Prevent Users from Submitting a Form Twice

<input type="submit" name="btnADD" id="btnADD" value="ADD"/>
when user click add button twice, from get submitted twice with same data into table.
So Please help me to restrict user to submit from twice.

Once the form is submitted, attach a handler with jQuery that hijacks and "disables" the submit handler:
var $myForm = $("#my_form");
$myForm.submit(function(){
$myForm.submit(function(){
return false;
});
});
Returning "false" from the submit handler will prevent the form from submitting. Disabling buttons can have weird effects on how the form is handled. This approach seems to basically lack side effects and works even on forms that have multiple submit buttons.

try out this code..
<input type="submit" name="btnADD" id="btnADD" value="ADD" onclick="this.disabled=true;this.value='Sending, please wait...';this.form.submit();" />

You can disable the button after clicking or hide it.
<input type="submit" name="btnADD" id="btnADD" value="ADD" onclick="disableButton(this)"/>
js :
function disableButton(button) {
button.disabled = true;
button.value = "submitting...."
button.form.submit();
}

If you are working with java server side scripting and also using struts 2 then you refer this link which talks about on using token.
http://www.xinotes.org/notes/note/369/
A token should be generated and kept in session for the initial page render, when the request is submitted along with the token for the first time , in struts action run a thread with thread name as the token id and run the logic whatever the client has requested for , when client submit again the same request, check whether the thread is still running(thread.getcurrentthread().interrupted) if still running then send a client redirect 503.
And if you are not using any framework and looking for simple workout.
You can take help of the
java.util.UUID.randomUUID();
Just put the random uuid in session and also in hidden form field and at other side(the jsp page where you are handling other work like storing data into database etc.) take out the uuid from session and hidden form field, If form field matches than proceed further, remove uuid from session and if not than it might be possible that the form has been resubmitted.
For your help i am writing some code snippet to give idea about how to achieve the thing.
<%
String formId=(java.util.UUID.randomUUID()).toString();
session.setAttribute(formId,formId);
%>
<input type='hidden' id='formId' name='formId' value='<%=formId%>'>

You could notify the user that he drinks too much coffee but the best is to disabled the button with javascript, for example like so:
$("#btnADD").on('click', function(btn) {
btn.disabled = true;
});

I made a solution based on rogueleaderr's answer:
jQuery('form').submit(function(){
jQuery(this).unbind('submit'); // unbind this submit handler first and ...
jQuery(this).submit(function(){ // added the new submit handler (that does nothing)
return false;
});
console.log('submitting form'); // only for testing purposes
});

My solution for a similar issue was to create a separate, hidden, submit button. It works like so:
You click the first, visible button.
The first button is disabled.
The onclick causes the second submit button to be pressed.
The form is submitted.
<input type="submit" value="Email" onclick="this.disabled=true; this.value='Emailing...'; document.getElementById('submit-button').click();">
<input type="submit" id='submit-button' value="Email" name="btnSubmitSendCertificate" style='display:none;'>
I went this route just for clarity for others working on the code. There are other solutions that may be subjectively better.

You can use JavaScript.
Attach form.submit.disabled = true; to the onsubmit event of the form.
A savvy user can circumvent it, but it should prevent 99% of users from submitting twice.

You can display successful message using a pop up with OK button when click OK redirect to somewhere else

Disable the Submit Button
$('#btnADD').attr('disabled','disabled');
or
$('#btnADD').attr('disabled','true');

When user click on submit button disable that button.
<form onSubmit="disable()"></form>
function disable()
{
document.getElementById('submitBtn').disabled = true;
//SUBMIT HERE
}

Create a class for the form, in my case I used: _submitlock
$(document).ready(function () {
$(document).on('submit', '._submitlock', function (event) {
// Check if the form has already been submitted
if (!$(this).hasClass('_submitted')) {
// Mark the form as submitted
$(this).addClass('_submitted');
// Update the attributes of the submit buttons
$(this).find('[type="submit"]').attr('disabled', 'disabled');
// Add classes required to visually change the state of the button
$(this).find('[type="submit"]').addClass("buttoninactive");
$(this).find('[type="submit"]').removeClass("buttonactive");
} else {
// Prevent the submit from occurring.
event.preventDefault();
}
});});

Put a class on all your buttons type="submit" like for example "button-disable-onsubmit" and use jQuery script like the following:
$(function(){
$(".button-disable-onsubmit").click(function(){
$(this).attr("disabled", "disabled");
$(this).closest("form").submit();
});
});
Remember to keep this code on a generic javascript file so you can use it in many pages. Like this, it becomes an elegant and easy-to-reuse solution.
Additionally you can even add another line to change the text value as well:
$(this).val("Sending, please wait.");

Add a class to the form when submitted, stopping a user double clicking/submitting
$('form[method=post]').each(function(){
$(this).submit(function(form_submission) {
if($(form_submission.target).attr('data-submitted')){
form_submission.preventDefault();
}else{
$(form_submission.target).attr('data-submitted', true);
}
});
});

You can add a class to your form and your submit button and use jquery:
$(function() {
// prevent the submit button to be pressed twice
$(".createForm").submit(function() {
$(this).find('.submit').attr('disabled', true);
$(this).find('.submit').text('Sending, please wait...');
});
})

None of these solutions worked for me as my form is a chat and repeated submits are also required. However I'm surprised this simple solution wasn't offered here which will work in all cases.
var sending = 0;
$('#myForm').submit(function(){
if (sending == 0){
sending++;
// SUBMIT FORM
}else{
return false;
}
setTimeout(function(){sending = 0;},1000); //RESET SENDING TO 0 AFTER ONE SECOND
}
This only allows one submit in any one second interval.

jquery click not getting triggered on IE

I've seen a lot of posts on this issue but none of the solutions worked. The following..
<script type="text/javascript">
$(document).ready(function() {
$("a.login_linkedinbutton").click(function(){
$("#signup-form").submit();
return false;
});
});
</script>
is what I have in the body tag of a page. Also in the body is the form, the html of which in IE shows up like this..
<form accept-charset="UTF-8" action="/auth/linkedin" class="well form-inline" id="signup-form" method="post">
<a class="login_linkedinbutton" href="#">Login using Linkedin</a>
</form>
in IE8, when the link within the form is clicked, the jquery is not getting triggered. It's working in Chrome and Firefox. I've tried:
1) Using the live event to bind the click action
2) Moved the jquery out of the page and into rails assets
Any ideas what else to try?

Use <input type="submit" value="Login using Linkedin">
Why create problems by using a non-standard element and then trying to recover from it?
If you want it to LOOK like a link, just style the button. But why do it? It's poor user experience to suggest the user to go to another page while they're submitting a form. Most users avoid clicking links when they have a form filled because they're afraid of loosing what they just typed.
If you insist using the link, you could try this:
var onLinkedInLogin = function(e){
e.preventDefault(); // stops the link processing
$("#signup-form").submit();
// add return false; if you want to stop event propagation also
// equivalent to calling both, e.preventDefault() and e.stopPropagation().
};
$(document).on('click', 'a.login_linkedinbutton', onLinkedInLogin);
The reason I'm suggesting using .on() instead on .click() is that I guess that on IE, the a.login_linkedinbutton is not present in the DOM when you call the .click().

OnClick bypasses form submit

I have a form which is made like this:
<form id= 'lol' name = 'whyyyyy'>
<input name='dumbo'>
<input name='idiot'>
<input type='submit' value='I have no idea why its like this' onclick='document.lol.submit()'>
</form>
Now, I want to prevent the actual sending of the form, but so far all attempts failed.
My current code looks like this:
$(document).ready(function(){
$('form[name="whyyyyy"]').submit(function(e){
e.preventDefault();
alert(1);
return false;
});
})
but the inline submit command bypasses as it seems the jQuery function.
Can someone shred light into it?
EDIT:
The form CANNOT be changed, I don't have permission to change.
the on click code should trigger the submit function, it some complex validation wall of code in it. So I have to cache the submit action that it triggers, but I can't do that at moment.
the submit function should be triggered on send but it does not get triggered.
Here is an example of the code in jfiddle. As you can see it gets past by jQuery...
http://jsfiddle.net/StCPp/4/

if you don't need a submit button, why don't you use a regular button instead
<input type="button" />

<input type='button' value='i have no idea why he done it like this' onclick='document.getElementById('lol').submit()'>

Just use a normal button instead of a submit.
If you want to bypass a submit button you can make the class of the button cancel.
<input type='submit' class='cancel' value='i have no idea why he done it like this' onclick='document.lol.submit()'>

In your add-on JavaScript, remove the inline onclick event and replace it with whatever you desire. Problem solved.
You could also completely remove his button and replace it with one of your choice.

Remove the document.lol.submit function. This way, you can do whatever you want.
// Magic line
delete document.lol.submit;
// Or
$('form[name="whyyyyy"] input[type=submit]').attr('onclick', '');
$(document).ready(function(){
$('form[name="whyyyyy"]').submit(function(e){
e.preventDefault();
alert(1);
return false;
});
});

Ok so if I got this right you could remove the inline event handler onclick and add your custom handler (where you do the validation and all necessary steps):
$(document).ready(function() {
var $submit_button = $('input[type=submit]');
$submit_button.removeAttr('onclick');
$submit_button.click(function() {
//TODO: implement your custom handler
//execute validation etc.
});
});

Remove the onclick
$('input[type=submit]').attr('onclick','')
Then add the click event to function ready
$('input[type=submit]').on('click',function(){
//do your event
});

You aren't necessarily required to use jquery to implement this. You could use standard javascript.
$(document).ready(function(){
document.whyyyyy.submit = function(e){
alert(1);
return false;
};
});
This example works, but you might be hitting a jquery bug.