Develop Reference

Choose only the first button

I'm trying to do that only one can happen, if you click yes or no. As it is now if you click "no" in the first time and "yes" in the second time, it will execute it twice .
function confirm() {
$("#no").one("click", function(){
return false;
});
}
$("#yes").one("click", function () {
//do something
});
thanks for help

Both events are attached at document.ready I assume, which means they will remain active indefinitely unless you specify otherwise.
The following approach is fairly basic, just set a variable 'hasClicked' to false. And as soon as either one of them is clicked, set 'hasClicked' to true. Each button has an if-structure that only executes the code IF 'hasClicked' is false.
Try the following:
var hasClicked = false;
function confirm(){
$("#no").one("click", function(){
if (!hasClicked){
hasClicked = true;
return false;
}
});
$("#yes").one("click", function () {
if (!hasClicked) {
hasClicked = true;
//do something
}
});
}

As you can't unbind an event binded with one() check this answer
So you'll have to work around like this:
function confirm() {
$("#no").bind("click", function(){
$(this).unbind(); // prevent other click events
$("#yes").unbind("click"); // prevent yes click event
// Do your stuff
});
}
$("#yes").bind("click", function () {
$(this).unbind();
$("#no").unbind("click");
// Do your stuff
});

Assign your buttons a class called confirmation. Set a event handler based on class. Read the value of the button to decide what you want to do.
$(".confirmation").one("click", function(){
if($(this).val() === 'yes'){
//do something
}else{
return false;
}
}

Intercept clicks, make some calls then resume what the click should have done before

Good day all, I have this task to do:
there are many, many many webpages, with any kind of element inside, should be inputs, buttons, links, checkboxes and so on, some time there should be a javascript that could handle the element behaviour, sometimes it is a simple ... link.
i have made a little javascript that intercepts all the clicks on clickable elements:
$( document ).ready(function() {
$('input[type=button], input[type=submit], input[type=checkbox], button, a').bind('click', function(evt, check) {
if (typeof check == 'undefined'){
evt.preventDefault();
console.log("id:"+ evt.target.id+", class:"+evt.target.class+", name:"+evt.target.name);
console.log (check);
$(evt.target).trigger('click', 'check');
}
});
});
the logic is: when something is cllicked, I intercept it, preventDefault it, make my track calls and then resme the click by trigger an event with an additional parameter that will not trigger the track call again.
but this is not working so good. submit clicks seams to work, but for example clicking on a checkbox will check it, but then it cannot be unchecked, links are simply ignored, I track them (in console.log() ) but then the page stay there, nothing happens.
maybe I have guessed it in the wrong way... maybe i should make my track calls and then bind a return true with something like (//...track call...//).done(return true); or something...
anyone has some suggestions?

If you really wanted to wait with the click event until you finished with your tracking call, you could probably do something like this. Here's an example for a link, but should be the same for other elements. The click event in this example fires after 2seconds, but in your case link.click() would be in the done() method of the ajax object.
google
var handled = {};
$("#myl").on('click', function(e) {
var link = $(this)[0];
if(!handled[link['id']]) {
handled[link['id']] = true;
e.preventDefault();
e.stopPropagation();
//simulate async ajax call
window.setTimeout(function() {link.click();}, 2000);
} else {
//reset
handled[link['id']] = false;
}
});
EDIT
So, for your example, this would look something like this
var handled = {};
$( document ).ready(function() {
$('input[type=button], input[type=submit], input[type=checkbox], button, a').bind('click', function(evt) {
if(!handled[evt.target.id]) {
handled[evt.target.id] = true;
evt.preventDefault();
evt.stopPropagation();
$.ajax({
url: 'your URL',
data: {"id" : evt.target.id, "class": evt.target.class, "name": evt.target.name},
done: function() {
evt.target.click();
}
});
} else {
handled[evt.target.id] = false;
}
});

How to disable the click if a function is in active status

I have created a fiddle of my function here( http://jsfiddle.net/rhy5K/10/ ) . Now i want to disable the button click i.e play/pause if the sound is playing like Get ready,5,4,3,2,1 .
I know only how to disable the form submit button , but I am very confused how to disable the click in my case the hyperlinks.
Explanation using code example:
I want to disable this
PLAY
click, while interpreter is executing the below code:
var playGetReady = function (done) {
var ids = ['audiosource', 'a_5', 'a_4', 'a_3', 'a_2', 'a_1'],
playNext = function () {
var id = ids.shift();
document.getElementById(id).play();
if (ids.length) {
setTimeout(playNext, 1000);
} else {
done();
}
};
playNext();
};
Warning: This JS fiddle demo may play sound on load

You may try this (Changes in following function), but not sure if this is you want and maybe there are other ways to do it.
App.prototype.start = function () {
var self = this;
// unbind for a while
self.$button.unbind('click', self.buttonHandler); // <--
var start = function () {
// start countdown
self.intervalHandle = setInterval($.proxy(self.tick, self), 1000);
// bind again
self.$button.click($.proxy(self.buttonHandler, self)); // <--
// change button text to PAUSE
self.$button.text('PAUSE');
};
if (this.newTimer) {
playGetReady(start);
} else {
start();
}
};
DEMO.

In jquery, it can be done easily by cancel default action. Here's the sample.
$("#btn_start").click(function(event){
if(not_active_flag){
// Prevent anchor to active
return false;
}else{
// Anchor active as usual
return true;
}
});

In your case, the link will ultimately call this.buttonHandler, which has the following code:
App.prototype.buttonHandler = function (e) {
e.preventDefault(); // prevent anchor default action
this.toggle(); // toggle play/pause
};
Because buttonHandler is attached before playGetReady is executed, it is not possible to let playGetReady attach a click handler to that anchor element that uses .stopImmediatePropagation() to prevent the other click handler from executing.
In this case #gp.'s solution in the comments is most likely the best solution. In your case you might even be able to use a local variable in your app. If you use a global variable, reference it with window.yourglobalvariable. If you use a local variable, make sure you define it somewhere and reference it with this.yourvariable. Change your buttonHandler to:
App.prototype.buttonHandler = function (e) {
e.preventDefault(); // prevent anchor default action
if( this.soundready )
this.toggle(); // toggle play/pause
};
On the appropiate place make this variable false to prevent the 'button' from working. When the button should work, change the variable to true. I think that should be just before done() in the code you have in your question, but you probably have a better idea in what order the code is executed.

Do not fire one event if already fired another

I have a code like this:
$('#foo').on('click', function(e) {
//do something
});
$('form input').on('change', function(e) {
//do some other things
));
First and second events do actually the same things with the same input field, but in different way. The problem is, that when I click the #foo element - form change element fires as well. I need form change to fire always when the content of input is changing, but not when #foo element is clicked.
That's the question )). How to do this?
Here is the code on jsfiddle: http://jsfiddle.net/QhXyj/1/

What happens is that onChange fires when the focus leaves the #input. In your case, this coincides with clicking on the button. Try pressing Tab, THEN clicking on the button.
To handle this particular case, one solution is to delay the call to the change event enough check if the button got clicked in the meantime. In practice 100 milisecond worked. Here's the code:
$().ready(function() {
var stopTheChangeBecauseTheButtonWasClicked = false;
$('#button').on('click', function(e) {
stopTheChangeBecauseTheButtonWasClicked = true;
$('#wtf').html("I don't need to change #input in this case");
});
$('#input').on('change', function(e) {
var self = this;
setTimeout(function doTheChange() {
if (!stopTheChangeBecauseTheButtonWasClicked) {
$(self).val($(self).val() + ' - changed!');
} else {
stopTheChangeBecauseTheButtonWasClicked = false;
}
}, 100);
});
});
And the fiddle - http://jsfiddle.net/dandv/QhXyj/11/

It's only natural that a change event on a blurred element fires before the clicked element is focused. If you don't want to use a timeout ("do something X ms after the input was changed unless in between a button was clicked", as proposed by Dan) - and timeouts are ugly - you only could go doing those actions twice. After the input is changed, save its state and do something. If then - somewhen later - the button is clicked, retrieve the saved state and do the something similar. I guess this is what you actually wanted for your UI behaviour, not all users are that fast. If one leaves the input (e.g. by pressing Tab), and then later activates the button "independently", do you really want to execute both actions?
var inputval = null, changedval = null;
$('form input').on('change', function(e) {
inputval = this.value;
// do some things with it and save them to
changedval = …
// you might use the value property of the input itself
));
$('#foo').on('click', function(e) {
// do something with inputval
});
$('form …').on('any other action') {
// you might want to invalidate the cache:
inputval = changedval;
// so that from now on a click operates with the new value
});

$(function() {
$('#button').on('click', function() {
//use text() not html() here
$('#wtf').text("I don't need to change #input in this case");
});
//fire on blur, that is when user types and presses tab
$('#input').on('blur', function() {
alert("clicked"); //this doesn't fire when you click button
$(this).val($(this).val()+' - changed!');
});
});​
Here's the Fiddle

$('form input').on('change', function(e) {
// don't do the thing if the input is #foo
if ( $(this).attrib('id') == 'foo' ) return;
//do some other things
));
UPDATE
How about this:
$().ready(function() {
$('#button').on('click', function(e) {
$('#wtf').html("I don't need to change #input in this case");
});
$('#input').on('change', function(e) {
// determine id #input is in focus
if ( ! $(this).is(":focus") ) return;
$(this).val($(this).val()+' - changed!');
});
});

What is the opposite of evt.preventDefault();

Once I've fired an evt.preventDefault(), how can I resume default actions again?

As per commented by #Prescott, the opposite of:
evt.preventDefault();
Could be:
Essentially equating to 'do default', since we're no longer preventing it.
Otherwise I'm inclined to point you to the answers provided by another comments and answers:
How to unbind a listener that is calling event.preventDefault() (using jQuery)?
How to reenable event.preventDefault?
Note that the second one has been accepted with an example solution, given by redsquare (posted here for a direct solution in case this isn't closed as duplicate):
$('form').submit( function(ev) {
ev.preventDefault();
//later you decide you want to submit
$(this).unbind('submit').submit()
});

function(evt) {evt.preventDefault();}
and its opposite
function(evt) {return true;}
cheers!

To process a command before continue a link from a click event in jQuery:
Eg: Click me
Prevent and follow through with jQuery:
$('a.myevent').click(function(event) {
event.preventDefault();
// Do my commands
if( myEventThingFirst() )
{
// then redirect to original location
window.location = this.href;
}
else
{
alert("Couldn't do my thing first");
}
});
Or simply run window.location = this.href; after the preventDefault();

OK ! it works for the click event :
$("#submit").click(function(event){
event.preventDefault();
// -> block the click of the sumbit ... do what you want
// the html click submit work now !
$("#submit").unbind('click').click();
});

event.preventDefault(); //or event.returnValue = false;
and its opposite(standard) :
event.returnValue = true;
source:
https://developer.mozilla.org/en-US/docs/Web/API/Event/returnValue

I had to delay a form submission in jQuery in order to execute an asynchronous call. Here's the simplified code...
$("$theform").submit(function(e) {
e.preventDefault();
var $this = $(this);
$.ajax('/path/to/script.php',
{
type: "POST",
data: { value: $("#input_control").val() }
}).done(function(response) {
$this.unbind('submit').submit();
});
});

I would suggest the following pattern:
document.getElementById("foo").onsubmit = function(e) {
if (document.getElementById("test").value == "test") {
return true;
} else {
e.preventDefault();
}
}
<form id="foo">
<input id="test"/>
<input type="submit"/>
</form>
...unless I'm missing something.
http://jsfiddle.net/DdvcX/

This is what I used to set it:
$("body").on('touchmove', function(e){
e.preventDefault();
});
And to undo it:
$("body").unbind("touchmove");

There is no opposite method of event.preventDefault() to understand why you first have to look into what event.preventDefault() does when you call it.
Underneath the hood, the functionality for preventDefault is essentially calling a return false which halts any further execution. If you’re familiar with the old ways of Javascript, it was once in fashion to use return false for canceling events on things like form submits and buttons using return true (before jQuery was even around).
As you probably might have already worked out based on the simple explanation above: the opposite of event.preventDefault() is nothing. You just don’t prevent the event, by default the browser will allow the event if you are not preventing it.
See below for an explanation:
;(function($, window, document, undefined)) {
$(function() {
// By default deny the submit
var allowSubmit = false;
$("#someform").on("submit", function(event) {
if (!allowSubmit) {
event.preventDefault();
// Your code logic in here (maybe form validation or something)
// Then you set allowSubmit to true so this code is bypassed
allowSubmit = true;
}
});
});
})(jQuery, window, document);
In the code above you will notice we are checking if allowSubmit is false. This means we will prevent our form from submitting using event.preventDefault and then we will do some validation logic and if we are happy, set allowSubmit to true.
This is really the only effective method of doing the opposite of event.preventDefault() – you can also try removing events as well which essentially would achieve the same thing.

Here's something useful...
First of all we'll click on the link , run some code, and than we'll perform default action. This will be possible using event.currentTarget Take a look. Here we'll gonna try to access Google on a new tab, but before we need to run some code.
Google
<script type="text/javascript">
$(document).ready(function() {
$("#link").click(function(e) {
// Prevent default action
e.preventDefault();
// Here you'll put your code, what you want to execute before default action
alert(123);
// Prevent infinite loop
$(this).unbind('click');
// Execute default action
e.currentTarget.click();
});
});
</script>

None of the solutions helped me here and I did this to solve my situation.
<a onclick="return clickEvent(event);" href="/contact-us">
And the function clickEvent(),
function clickEvent(event) {
event.preventDefault();
// do your thing here
// remove the onclick event trigger and continue with the event
event.target.parentElement.onclick = null;
event.target.parentElement.click();
}

I supose the "opposite" would be to simulate an event. You could use .createEvent()
Following Mozilla's example:
function simulateClick() {
var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", true, true, window,
0, 0, 0, 0, 0, false, false, false, false, 0, null);
var cb = document.getElementById("checkbox");
var cancelled = !cb.dispatchEvent(evt);
if(cancelled) {
// A handler called preventDefault
alert("cancelled");
} else {
// None of the handlers called preventDefault
alert("not cancelled");
}
}
Ref: document.createEvent
jQuery has .trigger() so you can trigger events on elements -- sometimes useful.
$('#foo').bind('click', function() {
alert($(this).text());
});
$('#foo').trigger('click');

This is not a direct answer for the question but it may help someone. My point is you only call preventDefault() based on some conditions as there is no point of having an event if you call preventDefault() for all the cases. So having if conditions and calling preventDefault() only when the condition/s satisfied will work the function in usual way for the other cases.
$('.btnEdit').click(function(e) {
var status = $(this).closest('tr').find('td').eq(3).html().trim();
var tripId = $(this).attr('tripId');
if (status == 'Completed') {
e.preventDefault();
alert("You can't edit completed reservations");
} else if (tripId != '') {
e.preventDefault();
alert("You can't edit a reservation which is already attached to a trip");
}
//else it will continue as usual
});

jquery on() could be another solution to this. escpacially when it comes to the use of namespaces.
jquery on() is just the current way of binding events ( instead of bind() ). off() is to unbind these. and when you use a namespace, you can add and remove multiple different events.
$( selector ).on("submit.my-namespace", function( event ) {
//prevent the event
event.preventDefault();
//cache the selector
var $this = $(this);
if ( my_condition_is_true ) {
//when 'my_condition_is_true' is met, the binding is removed and the event is triggered again.
$this.off("submit.my-namespace").trigger("submit");
}
});
now with the use of namespace, you could add multiple of these events and are able to remove those, depending on your needs.. while submit might not be the best example, this might come in handy on a click or keypress or whatever..

you can use this after "preventDefault" method
//Here evt.target return default event (eg : defult url etc)
var defaultEvent=evt.target;
//Here we save default event ..
if("true")
{
//activate default event..
location.href(defaultEvent);
}

You can always use this attached to some click event in your script:
location.href = this.href;
example of usage is:
jQuery('a').click(function(e) {
location.href = this.href;
});

In a Synchronous flow, you call e.preventDefault() only when you need to:
a_link.addEventListener('click', (e) => {
if( conditionFailed ) {
e.preventDefault();
// return;
}
// continue with default behaviour i.e redirect to href
});
In an Asynchronous flow, you have many ways but one that is quite common is using window.location:
a_link.addEventListener('click', (e) => {
e.preventDefault(); // prevent default any way
const self = this;
call_returning_promise()
.then(res => {
if(res) {
window.location.replace( self.href );
}
});
});
You can for sure make the above flow synchronous by using async-await

this code worked for me to re-instantiate the event after i had used :
event.preventDefault(); to disable the event.
event.preventDefault = false;

I have used the following code. It works fine for me.
$('a').bind('click', function(e) {
e.stopPropagation();
});