Manually click a child link (and navigate) when clicking parent [duplicate] - javascript

Recently I found jQuery cannot trigger the native click event on an anchor tag when I'm clicking on other elements, the example below won't work:
html
<a class="js-a1" href="new.html" target="_blank">this is a link</a>
<a class="js-a2" href="another.html" target="_blank">this is another link</a>
javascript
$('.js-a1').click(function () {
$('.js-a2').click();
return false;
});
And here is the jsfiddle - 1. Click on the first link won't trigger native click on the second one.
After some searches, I found a solution and an explanation.
Solution
Use the native DOM element.
$('.js-a1').click(function () {
$('.js-a2').get(0).click();
return false;
});
And here is the jsfiddle - 2.
Explanation
I found a post on Learn jQuery: Triggering Event Handlers. It told me:
The .trigger() function cannot be used to mimic native browser events, such as clicking on a file input box or an anchor tag. This is because, there is no event handler attached using jQuery's event system that corresponds to these events.
Question
So here comes my question:
How to understand 'there is no event handler attached using jQuery's event system that corresponds to these events'?
Why is there not such corresponding event handler?
EDIT
I update my jsfiddles, it seems there's and error on the class name.

there is no event handler attached using jQuery's event system that corresponds to these events
This means, at this point of the learning material, no jQuery event handlers has been attached to these elements using .click(function() {} or .bind('click', function () {}), etc.
The no-argument .click() is used to trigger (.trigger('click')) a "click" event from jQuery's perspective, which will execute all "click" event handlers registered by jQuery using .click, .bind, .on, etc. This pseudo event won't be sent to the browser.
.trigger()
Execute all handlers and behaviors attached to the matched elements for the given event type.
Check the updated jsFiddle example, click on the two links to see the difference. Hope it helps.

First of all you need to prevent the default behaviour of link
$('.js-a1').click(function (e) {
e.preventDefault();
$('.js-a2').get(0).click();
return false;
});
And to trigger the click event you can also use .trigger('click') better way
And the event handler is used like this:
$(document).on('click', '.js-a1',function(){//code in here});
// here now .js-a1 is event handler

i think you forgot to read documentation.
Document says :
// Triggering a native browser event using the simulate plugin
$( ".js-a2" ).simulate( "click" );

Old question, but here's a nifty and simple solution:
You can basically "register" a native JS event with jQuery by assigning the DOM element's onEvent handler to be the native event. Ideally, we would check first to ensure the onEvent handler has not already been set.
For example, 'register' the native JS click event so it will be triggered by jQuery:
$('.js-a1').click(function (e) {
$('.js-a2').click();
e.preventDefault();
});
var trigger_element = $('.js-a2')[0]; // native DOM element
if (!trigger_element.onclick) {
trigger_element.onclick = trigger_element.click;
}
Here is a fiddle: http://jsfiddle.net/f9vkd/162/

You have to use $("selector").trigger('click')

Related

jQuery remove scroll listener after reach certain point [duplicate]

I have an input type="image". This acts like the cell notes in Microsoft Excel. If someone enters a number into the text box that this input-image is paired with, I setup an event handler for the input-image. Then when the user clicks the image, they get a little popup to add some notes to the data.
My problem is that when a user enters a zero into the text box, I need to disable the input-image's event handler. I have tried the following, but to no avail.
$('#myimage').click(function { return false; });
jQuery ≥ 1.7
With jQuery 1.7 onward the event API has been updated, .bind()/.unbind() are still available for backwards compatibility, but the preferred method is using the on()/off() functions. The below would now be,
$('#myimage').click(function() { return false; }); // Adds another click event
$('#myimage').off('click');
$('#myimage').on('click.mynamespace', function() { /* Do stuff */ });
$('#myimage').off('click.mynamespace');
jQuery < 1.7
In your example code you are simply adding another click event to the image, not overriding the previous one:
$('#myimage').click(function() { return false; }); // Adds another click event
Both click events will then get fired.
As people have said you can use unbind to remove all click events:
$('#myimage').unbind('click');
If you want to add a single event and then remove it (without removing any others that might have been added) then you can use event namespacing:
$('#myimage').bind('click.mynamespace', function() { /* Do stuff */ });
and to remove just your event:
$('#myimage').unbind('click.mynamespace');
This wasn't available when this question was answered, but you can also use the live() method to enable/disable events.
$('#myimage:not(.disabled)').live('click', myclickevent);
$('#mydisablebutton').click( function () { $('#myimage').addClass('disabled'); });
What will happen with this code is that when you click #mydisablebutton, it will add the class disabled to the #myimage element. This will make it so that the selector no longer matches the element and the event will not be fired until the 'disabled' class is removed making the .live() selector valid again.
This has other benefits by adding styling based on that class as well.
This can be done by using the unbind function.
$('#myimage').unbind('click');
You can add multiple event handlers to the same object and event in jquery. This means adding a new one doesn't replace the old ones.
There are several strategies for changing event handlers, such as event namespaces. There are some pages about this in the online docs.
Look at this question (that's how I learned of unbind). There is some useful description of these strategies in the answers.
How to read bound hover callback functions in jquery
If you want to respond to an event just one time, the following syntax should be really helpful:
$('.myLink').bind('click', function() {
//do some things
$(this).unbind('click', arguments.callee); //unbind *just this handler*
});
Using arguments.callee, we can ensure that the one specific anonymous-function handler is removed, and thus, have a single time handler for a given event. Hope this helps others.
maybe the unbind method will work for you
$("#myimage").unbind("click");
I had to set the event to null using the prop and the attr. I couldn't do it with one or the other. I also could not get .unbind to work. I am working on a TD element.
.prop("onclick", null).attr("onclick", null)
If event is attached this way, and the target is to be unattached:
$('#container').on('click','span',function(eo){
alert(1);
$(this).off(); //seams easy, but does not work
$('#container').off('click','span'); //clears click event for every span
$(this).on("click",function(){return false;}); //this works.
});​
You may be adding the onclick handler as inline markup:
<input id="addreport" type="button" value="Add New Report" onclick="openAdd()" />
If so, the jquery .off() or .unbind() won't work. You need to add the original event handler in jquery as well:
$("#addreport").on("click", "", function (e) {
openAdd();
});
Then the jquery has a reference to the event handler and can remove it:
$("#addreport").off("click")
VoidKing mentions this a little more obliquely in a comment above.
If you use $(document).on() to add a listener to a dynamically created element then you may have to use the following to remove it:
// add the listener
$(document).on('click','.element',function(){
// stuff
});
// remove the listener
$(document).off("click", ".element");
To remove ALL event-handlers, this is what worked for me:
To remove all event handlers mean to have the plain HTML structure without all the event handlers attached to the element and its child nodes. To do this, jQuery's clone() helped.
var original, clone;
// element with id my-div and its child nodes have some event-handlers
original = $('#my-div');
clone = original.clone();
//
original.replaceWith(clone);
With this, we'll have the clone in place of the original with no event-handlers on it.
Good Luck...
Updated for 2014
Using the latest version of jQuery, you're now able to unbind all events on a namespace by simply doing $( "#foo" ).off( ".myNamespace" );
Best way to remove inline onclick event is $(element).prop('onclick', null);
Thanks for the information. very helpful i used it for locking page interaction while in edit mode by another user. I used it in conjunction with ajaxComplete. Not necesarily the same behavior but somewhat similar.
function userPageLock(){
$("body").bind("ajaxComplete.lockpage", function(){
$("body").unbind("ajaxComplete.lockpage");
executePageLock();
});
};
function executePageLock(){
//do something
}
In case .on() method was previously used with particular selector, like in the following example:
$('body').on('click', '.dynamicTarget', function () {
// Code goes here
});
Both unbind() and .off() methods are not going to work.
However, .undelegate() method could be used to completely remove handler from the event for all elements which match the current selector:
$("body").undelegate(".dynamicTarget", "click")
I know this comes in late, but why not use plain JS to remove the event?
var myElement = document.getElementById("your_ID");
myElement.onclick = null;
or, if you use a named function as an event handler:
function eh(event){...}
var myElement = document.getElementById("your_ID");
myElement.addEventListener("click",eh); // add event handler
myElement.removeEventListener("click",eh); //remove it
This also works fine .Simple and easy.see http://jsfiddle.net/uZc8w/570/
$('#myimage').removeAttr("click");
if you set the onclick via html you need to removeAttr ($(this).removeAttr('onclick'))
if you set it via jquery (as the after the first click in my examples above) then you need to unbind($(this).unbind('click'))
All the approaches described did not work for me because I was adding the click event with on() to the document where the element was created at run-time:
$(document).on("click", ".button", function() {
doSomething();
});
My workaround:
As I could not unbind the ".button" class I just assigned another class to the button that had the same CSS styles. By doing so the live/on-event-handler ignored the click finally:
// prevent another click on the button by assigning another class
$(".button").attr("class","buttonOff");
Hope that helps.
Hope my below code explains all.
HTML:
(function($){
$("#btn_add").on("click",function(){
$("#btn_click").on("click",added_handler);
alert("Added new handler to button 1");
});
$("#btn_remove").on("click",function(){
$("#btn_click").off("click",added_handler);
alert("Removed new handler to button 1");
});
function fixed_handler(){
alert("Fixed handler");
}
function added_handler(){
alert("new handler");
}
$("#btn_click").on("click",fixed_handler);
$("#btn_fixed").on("click",fixed_handler);
})(jQuery);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="btn_click">Button 1</button>
<button id="btn_add">Add Handler</button>
<button id="btn_remove">Remove Handler</button>
<button id="btn_fixed">Fixed Handler</button>
I had an interesting case relevant to this come up at work today where there was a scroll event handler for $(window).
// TO ELIMINATE THE RE-SELECTION AND
// RE-CREATION OF THE SAME OBJECT REDUNDANTLY IN THE FOLLOWING SNIPPETS
let $window = $(window);
$window.on('scroll', function() { .... });
But, to revoke that event handler, we can't just use
$window.off('scroll');
because there are likely other scroll event handlers on this very common target, and I'm not interested in hosing that other functionality (known or unknown) by turning off all of the scroll handlers.
My solution was to first abstract the handler functionality into a named function, and use that in the event listener setup.
function handleScrollingForXYZ() { ...... }
$window.on('scroll', handleScrollingForXYZ);
And then, conditionally, when we need to revoke that, I did this:
$window.off('scroll', $window, handleScrollingForXYZ);
The janky part is the 2nd parameter, which is redundantly selecting the original selector. But, the jquery documentation for .off() only provides one method signature for specifying the handler to remove, which requires this middle parameter to be
A selector which should match the one originally passed to .on() when attaching event handlers.
I haven't ventured to test it out with a null or '' as the 2nd parameter, but perhaps the redundant $window isn't necessary.

Simulate clicking a button

If I have an existing click event associated with a button, can I use code to simulate that button being pressed so the code in the click event will run? I'm asking because I want there to be certain times where the user does not have to press the button for code to be executed. I would like to press the button automatically for them in certain instances if that makes any sense.
As simple as this,
$(function() {
$('#button').trigger('click');
});
var button = document.getElementById('yourButtonIdHere');
button.click();
This will fire a click event in the button
You can trigger a click event on an element by calling the .click() function on the element. By passing no value to the function the click event will fire, as opposed to setting up a listener for the click event.
If the button has an id of "form-btn", here's what that would like:
<button id="form-btn">Submit</button>
<script type="text/javascript">
//Setup the click event
$('#form-btn').on('click', function (e) {
alert('clicked!');
});
//Call the click event
$('#form-btn').click();
</script>
This should work fine, although I usually try to use a named function when setting up my event handlers, instead of anonymous functions. By doing so, rather than triggering the event I can call the function directly.
Note that in my experience, older browsers (IE6, IE7) sometimes limit what code-triggered events can do as a safety precaution for the user.
Here's documentation on the .click() function: http://www.w3schools.com/jquery/event_click.asp
Edit 1
I forgot that jQuery also has the .trigger() function, as used in choz's answer. That will also the job quite nicely as an alternative to .click(). What's nice about .trigger() is that it can trigger standard events as well as custom events, and also allow you to pass more data in your event.
Just make a function and run the function from within the button.
Three Choices:
You can call the click event handling function directly when appropriate:
if(timeIsRightForClick){
yourClickHandler();
}
You can simulate a button click by calling the .click() method of the button.
$("#ButtonID").click()
https://api.jquery.com/click/
Same as #2, but using jQuery's trigger() function, which can be used on standard events and custom ones:
$("#ButtonID").trigger("click");
http://api.jquery.com/trigger/
Choices #2 and #3 are usually better because they will cause the event handling function to receive a reference to the click event in case it needs to use that object. Choice #1 doesn't cause an actual click event (just runs the code you tell it to) and so no event object is created or passed to the event handler.

Capture only hashchange events not resulting from anchor clicks

I am trying to use Javascript to emulate the CSS :target pseudo-class so as to capture all events that result in an element on page being targeted. I've identified 3 trigger events:
window.location.hash already targets an element of the same ID on initialisation
An anchor targeting the element is clicked
The hashchange event is fired independently of the above (for example via the window.history API)
Scenario 2 is important as a distinct case since I would want to invoke the click event's preventDefault. The simplified code for this scenario follows:
$('body').on('click', 'a[href*=#]', function filterTarget(clickEvent){
$(this.hash).trigger('target', [clickEvent]);
});
The problem comes when trying to implement scenario 3:
$(window).on('hashchange', function filterTarget(hashChangeEvent){
$(this.hash).trigger('target', [hashChangeEvent]);
});
If a target handler doesn't cancel the native behaviour for scenario 2, it will be triggered again when the native behaviour causes the resulting hashchange event. How can I filter out these edge cases?
POST-SOLUTION EDIT:
roasted's answer held the key — handle a namespaced hashchange event, then unbind and rebind the handler based on logic handled inside the click handler and its preventDefault. I wrote up the full plugin here.
If i understand it, you don't want the hashchange event to be fired if an anchor tag is clicked. You could then set your logic using namespaced events:
DEMO
$('body').on('click', 'a[href*=#]', function (clickEvent) {
filterTarget(clickEvent,this);
$(window).off('hashchange.filter').on('hashchange.tmp', function () {
$(this).off('hashchange.tmp').on('hashchange.filter', filterTarget);
});
});
$(window).on('hashchange.filter', filterTarget);
function filterTarget(event,elem) {
$(elem?elem.hash:window.location.hash).trigger('target', [event]);
//you could filter depending event.type
alert(event.type + '::'+ (elem?elem.hash:window.location.hash));
}
if the click is setting the hash with the fragment anyway, just throw away duplicates in the hash change event:
onhashchange=function(e){
if(e.newURL == e.oldURL ){return; }
//do your normal hashchange event stuff below:
};
ref: https://developer.mozilla.org/en-US/docs/Web/API/window.onhashchange
this fixes cascade issues no matter what invoked the change.
Seems like you could use mousedown instead of click, if you're going to be calling preventDefault on it. Then presumably the hashchange would not be triggered.

jQuery click events overriding each other

I have the following jQuery:
$('.io-sidebar-section').click(function () {
console.log('Section Clicked');
$(this).next().fadeToggle('fast',function(){});
});
$('.io-sidebar-section-advanced-toggle').click(function(){
$(this).parent().next().children('.io-sidebar-link-advanced').fadeToggle('fast',function(){});
});
the advanced toggle is inside of a sidebar section. When I click on the advanced toggle, it executes the sidebar section click.
How can I seperate these two out?
You can use the stopPropagation method of the event object inside the click event handler for the child element:
$('.io-sidebar-section-advanced-toggle').click(function(e){
e.stopPropagation();
$(this).parent().next().children('.io-sidebar-link-advanced').fadeToggle('fast',function(){});
});
From the jQuery docs, here's what stopPropagation does:
Prevents the event from bubbling up the DOM tree, preventing any
parent handlers from being notified of the event.
As mentioned in the comments, if you prefer you can alternatively use return false in the event handler (in this particular case, as far as I can tell anyway - it will also cause preventDefault which may not be what you want to happen). My personal preference is to use stopPropagation but it's completely up to you.
You can avoid events bubbling up by using jQuery's bind function and preventBubble argument.
http://api.jquery.com/bind/

jQuery programmatically trigger events

What all events can be triggered programmatically using jQuery? Also is there any important differences to be remembered when one is doing event triggering using jQuery Vs a natural way of it being triggered?
Every event can be programmatically fired, just use the callback-less version of it.
Example:
$('#button').click(function() { alert('event hanlder'); });
$('#button').click(); // generate the event
About your second question, there should be no difference between the native and jQuery event handlers.
One thing that is neat though is that jQuery binds this to the element that received the event, inside the callback (this doesn't happen in native event handlers):
$('#button').click(function() { alert(this); }); // here 'this' == document.getElementById('button');
Warning: the element referenced by this is not "jQuery augmented". If you want to traverse or modify it with jQuery goodness you'll have to do something like var $this = $(this);
You should know the differences between trigger and triggerHandler in jQuery.
trigger
trigger attempts to replicate the natural event as best as it can. The event handler for the event being triggered get's executed, but the default browser actions will not always be replicated exactly. For example $('a#link).trigger('click'); will execute the javascript function bound to the links click event handler, but will not redirect the browser to the href of the anchor, like a normal click would. EX: http://jsfiddle.net/AxFkD/
All the short forms of the trigger call behave exactly like trigger IE. click(), mouseup(), keydown(), etc
triggerHandler
triggerHandler prevents bubbling up ( EX. http://jsfiddle.net/LmqsS/ ), it avoids default browser behaviour and just executes the events callback, and it returns the return value of the event handler instead of a jQUery object for chaining.
You should also be aware that trigger affects all elements matched by a selector, but triggerHandler only affects the first one EX: http://jsfiddle.net/jvnyS/
You can trigger any event programmatically. But most of the events cannot be simulated as the natural event using programmatic triggers.
//to trigger a click event on a button
$("buttonSelector").trigger("click");
First, for obvious reasons, you cannot trigger the ready event.
That said, events raised by trigger() behave the same way as if they were triggered by the user. In particular, the event handlers are called in the same order.
The only difference I know of is that triggered events did not bubble up the DOM tree in older versions of jQuery (that behavior was fixed in version 1.3).

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