We Keep Coding

Stop propagation on custom event through callback

I'm not sure how to word it, this is what I'm trying to accomplish:
$(document).on('click', '.my-element', function(e) {
var data = [{
'event': e,
'self': this
}];
// Trigger the override function first in case they need to stop prop
$(document).trigger('override:something',dataa);
// Would like to only trigger this default method if the event above is not set
$(document).trigger('something',data);
});
Then on another page I have something to catch this event, like so:
$(document).on('override:something', function(e,data) {
e.stopImmediatePropagation();
data.e.stopImmediatePropagation(); // neither work
});
If I could stop all subsequent events like this that would be optimal, but I could also make it work if there were a way to check if custom events are set.
I could check whether override:something exists and if it does, do not execute the default something event afterwards.
I've tried setting removing specific callbacks like this, but it did not perform as expected and could get hard to manage.
var mycb = function() {
alert('hi');
}
$(document).on('something', mycb);
// now to remove it
$(document).off('something', mycb); // does not remove the event
Any help is greatly appreciated.

Thanks for the help guys, but this solution seems to the only thing I've found to work for now. Still accepting alternate answers, though.
var override = jQuery._data($(document)[0], 'events')['override:something'];
$(document).trigger('override:something', data);
if ( typeof override == typeof undefined )
$(document).trigger('dashboard:friend', data);

Prepend event listener [duplicate]

Lets say I have a web app which has a page that may contain 4 script blocks - the script I write may be found in one of those blocks, but I do not know which one, that is handled by the controller.
I bind some onclick events to a button, but I find that they sometimes execute in an order I did not expect.
Is there a way to ensure order, or how have you handled this problem in the past?

If order is important you can create your own events and bind callbacks to fire when those events are triggered by other callbacks.
$('#mydiv').click(function(e) {
// maniplate #mydiv ...
$('#mydiv').trigger('mydiv-manipulated');
});
$('#mydiv').bind('mydiv-manipulated', function(e) {
// do more stuff now that #mydiv has been manipulated
return;
});
Something like that at least.

Dowski's method is good if all of your callbacks are always going to be present and you are happy with them being dependant on each other.
If you want the callbacks to be independent of each other, though, you could be to take advantage of bubbling and attach subsequent events as delegates to parent elements. The handlers on a parent elements will be triggered after the handlers on the element, continuing right up to the document. This is quite good as you can use event.stopPropagation(), event.preventDefault(), etc to skip handlers and cancel or un-cancel the action.
$( '#mybutton' ).click( function(e) {
// Do stuff first
} );
$( '#mybutton' ).click( function(e) {
// Do other stuff first
} );
$( document ).delegate( '#mybutton', 'click', function(e) {
// Do stuff last
} );
Or, if you don't like this, you could use Nick Leaches bindLast plugin to force an event to be bound last: https://github.com/nickyleach/jQuery.bindLast.
Or, if you are using jQuery 1.5, you could also potentially do something clever with the new Deferred object.

I had been trying for ages to generalize this kind of process, but in my case I was only concerned with the order of first event listener in the chain.
If it's of any use, here is my jQuery plugin that binds an event listener that is always triggered before any others:
** UPDATED inline with jQuery changes (thanks Toskan) **
(function($) {
$.fn.bindFirst = function(/*String*/ eventType, /*[Object])*/ eventData, /*Function*/ handler) {
var indexOfDot = eventType.indexOf(".");
var eventNameSpace = indexOfDot > 0 ? eventType.substring(indexOfDot) : "";
eventType = indexOfDot > 0 ? eventType.substring(0, indexOfDot) : eventType;
handler = handler == undefined ? eventData : handler;
eventData = typeof eventData == "function" ? {} : eventData;
return this.each(function() {
var $this = $(this);
var currentAttrListener = this["on" + eventType];
if (currentAttrListener) {
$this.bind(eventType, function(e) {
return currentAttrListener(e.originalEvent);
});
this["on" + eventType] = null;
}
$this.bind(eventType + eventNameSpace, eventData, handler);
var allEvents = $this.data("events") || $._data($this[0], "events");
var typeEvents = allEvents[eventType];
var newEvent = typeEvents.pop();
typeEvents.unshift(newEvent);
});
};
})(jQuery);
Things to note:
This hasn't been fully tested.
It relies on the internals of the jQuery framework not changing (only tested with 1.5.2).
It will not necessarily get triggered before event listeners that are bound in any way other than as an attribute of the source element or using jQuery bind() and other associated functions.

The order the bound callbacks are called in is managed by each jQuery object's event data. There aren't any functions (that I know of) that allow you to view and manipulate that data directly, you can only use bind() and unbind() (or any of the equivalent helper functions).
Dowski's method is best, you should modify the various bound callbacks to bind to an ordered sequence of custom events, with the "first" callback bound to the "real" event. That way, no matter in what order they are bound, the sequence will execute in the right way.
The only alternative I can see is something you really, really don't want to contemplate: if you know the binding syntax of the functions may have been bound before you, attempt to un-bind all of those functions and then re-bind them in the proper order yourself. That's just asking for trouble, because now you have duplicated code.
It would be cool if jQuery allowed you to simply change the order of the bound events in an object's event data, but without writing some code to hook into the jQuery core that doesn't seem possible. And there are probably implications of allowing this that I haven't thought of, so maybe it's an intentional omission.

Please note that in the jQuery universe this must be implemented differently as of version 1.8. The following release note is from the jQuery blog:
.data(“events”): jQuery stores its event-related data in a data object
named (wait for it) events on each element. This is an internal data
structure so in 1.8 this will be removed from the user data name space
so it won’t conflict with items of the same name. jQuery’s event data
can still be accessed via jQuery._data(element, "events")
We do have complete control of the order in which the handlers will execute in the jQuery universe. Ricoo points this out above. Doesn't look like his answer earned him a lot of love, but this technique is very handy. Consider, for example, any time you need to execute your own handler prior to some handler in a library widget, or you need to have the power to cancel the call to the widget's handler conditionally:
$("button").click(function(e){
if(bSomeConditional)
e.stopImmediatePropagation();//Don't execute the widget's handler
}).each(function () {
var aClickListeners = $._data(this, "events").click;
aClickListeners.reverse();
});

function bindFirst(owner, event, handler) {
owner.unbind(event, handler);
owner.bind(event, handler);
var events = owner.data('events')[event];
events.unshift(events.pop());
owner.data('events')[event] = events;
}

just bind handler normally and then run:
element.data('events').action.reverse();
so for example:
$('#mydiv').data('events').click.reverse();

You can try something like this:
/**
* Guarantee that a event handler allways be the last to execute
* #param owner The jquery object with any others events handlers $(selector)
* #param event The event descriptor like 'click'
* #param handler The event handler to be executed allways at the end.
**/
function bindAtTheEnd(owner,event,handler){
var aux=function(){owner.unbind(event,handler);owner.bind(event,handler);};
bindAtTheStart(owner,event,aux,true);
}
/**
* Bind a event handler at the start of all others events handlers.
* #param owner Jquery object with any others events handlers $(selector);
* #param event The event descriptor for example 'click';
* #param handler The event handler to bind at the start.
* #param one If the function only be executed once.
**/
function bindAtTheStart(owner,event,handler,one){
var eventos,index;
var handlers=new Array();
owner.unbind(event,handler);
eventos=owner.data("events")[event];
for(index=0;index<eventos.length;index+=1){
handlers[index]=eventos[index];
}
owner.unbind(event);
if(one){
owner.one(event,handler);
}
else{
owner.bind(event,handler);
}
for(index=0;index<handlers.length;index+=1){
owner.bind(event,ownerhandlers[index]);
}
}

I have same issue and found this topic. the above answers can solve those problem, but I don't think them are good plans.
let us think about the real world.
if we use those answers, we have to change our code. you have to change your code style. something like this:
original:
$('form').submit(handle);
hack:
bindAtTheStart($('form'),'submit',handle);
as time goes on, think about your project. the code is ugly and hard to read! anthoer reason is simple is always better. if you have 10 bindAtTheStart, it may no bugs. if you have 100 bindAtTheStart, are you really sure you can keep them in right order?
so if you have to bind same events multiple.I think the best way is control js-file or js-code load order. jquery can handle event data as queue. the order is first-in, first-out. you don't need change any code. just change load order.

Here's my shot at this, covering different versions of jQuery:
// Binds a jQuery event to elements at the start of the event chain for that type.
jQuery.extend({
_bindEventHandlerAtStart: function ($elements, eventType, handler) {
var _data;
$elements.bind(eventType, handler);
// This bound the event, naturally, at the end of the event chain. We
// need it at the start.
if (typeof jQuery._data === 'function') {
// Since jQuery 1.8.1, it seems, that the events object isn't
// available through the public API `.data` method.
// Using `$._data, where it exists, seems to work.
_data = true;
}
$elements.each(function (index, element) {
var events;
if (_data) {
events = jQuery._data(element, 'events')[eventType];
} else {
events = jQuery(element).data('events')[eventType];
}
events.unshift(events.pop());
if (_data) {
jQuery._data(element, 'events')[eventType] = events;
} else {
jQuery(element).data('events')[eventType] = events;
}
});
}
});

In some special cases, when you cannot change how the click events are bound (event bindings are made from others' codes), and you can change the HTML element, here is a possible solution (warning: this is not the recommended way to bind events, other developers may murder you for this):
<span onclick="yourEventHandler(event)">Button</span>
With this way of binding, your event hander will be added first, so it will be executed first.

JQuery 1.5 introduces promises, and here's the simplest implementation I've seen to control order of execution. Full documentation at http://api.jquery.com/jquery.when/
$.when( $('#myDiv').css('background-color', 'red') )
.then( alert('hi!') )
.then( myClickFunction( $('#myID') ) )
.then( myThingToRunAfterClick() );

How remove onClick, and then add it again later?

I need a method to enable and disable any element. Disable meaning set the opacity to 0.6 and remove the onClick callbacks. Enable meaning set the opacity to 1 and add the callback again.
My first two attempts failed miserably, the callback methods just got stacked and instead of running it once after each click the method was running more and more times.
function disableElement(element){
var el = $('#'+element);
el.css('opacity','0.6');
el.on('click',null); //this doesn't work
el.removeAttr('onClick'); // this doesn't help either.
}
function enableElement(element,callback){
var el = $('#'+element);
el.css('opacity','1');
el.on('click',callback);
}
Then i tried using the el.data:
disableElement:function(element){
var el = $('#'+element);
el.css('opacity','0.6');
el.data('element-enabled','false');
//el.click(function (){
// alert('disabled');
//});
},
enableElement:function(element,callback){
console.log('enabling');
var el = $('#'+element);
console.log(el);
if(el.data('element-enabled') == "true")
return;
console.log("setOpacity");
el.css('opacity','1');
el.data('element-enabled','true');
el.click(function(){
if(el.data('element-enabled') == "true")
callback();
});
}
Now they don't stack, as long as I don't disable it. If I disable and then enable it again, it gets stacked. Which means, if i run enableElement multiple times the callbacks don't stack. But once I run disableElement and then enableElement, if i click in the item, it'll happen twice.
Can achieve that somehow?
UPDATE
That was close. The off worked for me but i also had to remove it on the enableElement. Occasionally I have to call it twice, so it was still stacking. Finally this worked, thank you!
disableElement:function(element){
var el = $('#'+element);
el.css('opacity','0.6');
el.off('click');
},
enableElement:function(element,callback){
var el = $('#'+element);
el.off('click');
el.css('opacity','1');
el.on('click',callback);
}

To remove the event just use .off()
el.off('click');
To add the event back you can just do
el.on('click',callback);

You need to use .off as in .off('click'). That will remove all bound events of the click type. Documentation for .off
Note that if you use .off it doesn't return the event or anything, and you can't simply rebind with .on. However, since you have defined the callback in a separate function, you're good to go since you do re-bind as .on('click', function_name). It's just something to be aware of.

Unbind will remove all handlers assigned to the object for some event:
$('#foo').unbind('click');
You can also set this to some specific function by adding it as a second argument
$('#foo').unbind('click', myfunctionname);

Why are these nested triggers for jQuery not working?

I am using the following code to load two underscore.js templates. Once the first link is clicked, the skeleton template is loaded. The first trigger executes the find bind, which executes the loadBookmarks function correctly, but the 'loaded' trigger never fires and the loadFriendBookmarks never executes. Why is this? Is there another way to make this happen?
$('#bookmarks-link').click(function() {
$('#bookmarks-count').text("0");
var skeleton = modalTemplate();
$('#bookmarks').append(skeleton);
$('#bookmarks').trigger('skeleton');
});
$('#bookmarks').bind('skeleton', function() {
$('#bookmarks .thumbnails').loadBookmarks( getBookmarksUrl(1) );
// If I add an alert('hi') here, it works perfectly.
$('#bookmarks').trigger('loaded');
});
$('#bookmarks').bind('loaded', function() {
$('#bookmarks .thumbnails a').each(function() {
$(this).bind('click', function() {
$('#bookmarks .bookmarks-table tbody').empty();
$('#bookmarks .bookmarks-table tbody').loadFriendBookmarks(
getFriendBookmarksUrl($(this).attr('data-item'))
);
});
});
});
So interesting enough, the triggers do work correctly: If I stick an alert in between loadBookmarks and trigger, everything works fine. If I take it out, then it doesn't. Any idea why?

Based on your description and common sense, it sounds like loadBookmarks() loads data from a remote source, such as an ajax call. This means that trigger('loaded') can fire before loadBookmarks() has received the data. You can add a callback argument to loadBookmarks() and trigger the event there:
$('#bookmarks .thumbnails').loadBookmarks( getBookmarksUrl(1) , function() {
$('#bookmarks').trigger('loaded');
});
But this requires your loadBookmarks to know to call this function after it receives the data and creates the needed HTML - I can't demonstrate this without seeing the actual code you have in loadBookmarks.
Additional suggestion: don't bind handlers this way, use event delegation instead:
$('#bookmarks').on('click', '.thumbnails a', function(e) {
e.preventDefault(); // don't want the link to actually be followed, do we
var url = getFriendBookmarksUrl($(this).attr('data-item'));
if(url) { // in case it's clicked before the data attribute is set
var $tbody = $('#bookmarks .bookmarks-table tbody');
$tbody.empty();
$tbody.loadFriendBookmarks(url);
}
});
This means that all elements matching the selector '#bookmarks .thumbnails a' will call this click handler, even if they were added to the document after you called on. Meaning you can delegate these events even before calling loadBookmarks, removing the need for the loaded event at all. Plus, this way you only have one copy of the handler function in memory, as opposed to your bind which created a separate copy of the function for each a node.

the problem is else where in your code. probably some js error in loadBookmarks* functions.
see:
http://jsfiddle.net/BBESV/
triggers work perfectly

How can I programmatically invoke an onclick() event from a anchor tag while keeping the ‘this’ reference in the onclick function?

The following doesn't work... (at least not in Firefox: document.getElementById('linkid').click() is not a function)
<script type="text/javascript">
function doOnClick() {
document.getElementById('linkid').click();
//Should alert('/testlocation');
}
</script>
<a id="linkid" href="/testlocation" onclick="alert(this.href);">Testlink</a>

You need to apply the event handler in the context of that element:
var elem = document.getElementById("linkid");
if (typeof elem.onclick == "function") {
elem.onclick.apply(elem);
}
Otherwise this would reference the context the above code is executed in.

The best way to solve this is to use Vanilla JS, but if you are already using jQuery, there´s a very easy solution:
<script type="text/javascript">
function doOnClick() {
$('#linkid').click();
}
</script>
<a id="linkid" href="/testlocation" onclick="alert(this.href);">Testlink</a>
Tested in IE8-10, Chrome, Firefox.

To trigger an event you basically just call the event handler for that
element. Slight change from your code.
var a = document.getElementById("element");
var evnt = a["onclick"];
if (typeof(evnt) == "function") {
evnt.call(a);
}

Granted, OP stated very similarly that this didn't work, but it did for me. Based on the notes in my source, it seems it was implemented around the time, or after, OP's post. Perhaps it's more standard now.
document.getElementsByName('MyElementsName')[0].click();
In my case, my button didn't have an ID. If your element has an id, preferably use the following (untested).
document.getElementById('MyElementsId').click();
I originally tried this method and it didn't work. After Googling I came back and realized my element was by name, and didn't have an ID. Double check you're calling the right attribute.
Source: https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/click

$("#linkid").trigger("click");

Old thread, but the question is still relevant, so...
(1) The example in your question now DOES work in Firefox. However in addition to calling the event handler (which displays an alert), it ALSO clicks on the link, causing navigation (once the alert is dismissed).
(2) To JUST call the event handler (without triggering navigation) merely replace:
document.getElementById('linkid').click();
with
document.getElementById('linkid').onclick();

Have a look at the handleEvent method
https://developer.mozilla.org/en-US/docs/Web/API/EventListener
"Raw" Javascript:
function MyObj() {
this.abc = "ABC";
}
MyObj.prototype.handleEvent = function(e) {
console.log("caught event: "+e.type);
console.log(this.abc);
}
var myObj = new MyObj();
document.querySelector("#myElement").addEventListener('click', myObj);
Now click on your element (with id "myElement") and it should print the following in the console:
caught event: click
ABC
This allows you to have an object method as event handler, and have access to all the object properties in that method.
You can't just pass a method of an object to addEventListener directly (like that: element.addEventListener('click',myObj.myMethod);) and expect myMethod to act as if I was normally called on the object. I am guessing that any function passed to addEventListener is somehow copied instead of being referenced. For example, if you pass an event listener function reference to addEventListener (in the form of a variable) then unset this reference, the event listener is still executed when events are caught.
Another (less elegant) workaround to pass a method as event listener and stil this and still have access to object properties within the event listener would be something like that:
// see above for definition of MyObj
var myObj = new MyObj();
document.querySelector("#myElement").addEventListener('click', myObj.handleEvent.bind(myObj));

If you're using this purely to reference the function in the onclick attribute, this seems like a very bad idea. Inline events are a bad idea in general.
I would suggest the following:
function addEvent(elm, evType, fn, useCapture) {
if (elm.addEventListener) {
elm.addEventListener(evType, fn, useCapture);
return true;
}
else if (elm.attachEvent) {
var r = elm.attachEvent('on' + evType, fn);
return r;
}
else {
elm['on' + evType] = fn;
}
}
handler = function(){
showHref(el);
}
showHref = function(el) {
alert(el.href);
}
var el = document.getElementById('linkid');
addEvent(el, 'click', handler);
If you want to call the same function from other javascript code, simulating a click to call the function is not the best way. Consider:
function doOnClick() {
showHref(document.getElementById('linkid'));
}

In general I would recommend against calling the event handlers 'manually'.
It's unclear what gets executed because of multiple registered
listeners
Danger to get into a recursive and infinite event-loop (click A
triggering Click B, triggering click A, etc.)
Redundant updates to the DOM
Hard to distinguish actual changes in the view caused by the user from changes made as initialisation code (which should be run only once).
Better is to figure out what exactly you want to have happen, put that in a function and call that manually AND register it as event listener.