Problem with jquery button click - javascript

I am facing a problem in the jquery click event.
My web page involves creating a button through javascript and assigning a class to the button ( call it A ). Now I want to detect the click of that button and I have written the following code for it :
$(".A").click( function () {
// do something
});
To my surprise, this click event never gets called.
But when I make the button statically on the webpage ( during design time ), the same code works.
Is there a different approach to bind a button click with jquery in case a button is created dynamically?

You need to use $.live
$(".A").live('click', function () {
// do something
});

Have a look at the live() jquery method to automatically wire up events to new elements. Or, as you create the new button, attach the new click event.
var newbutton = $('<input type="button" value="click me"/>');
somediv.append(newbutton);
newbutton.click(yourhandler);

Your event handler fires at page load, before your button exists.
Either reset the event handler after you create the button, or use .live for late-binding:
$(".A").live('click', function () {
// do something
});
Now the handler will apply to .A even created in the future.

you have to use the live-function of jquery! In difference to the click-function, it watches for dom manipulations. as you can imagine its slightly slower than the .click().
$('.clickme').live('click', function() {
// Live handler called.
});
Felix

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.

Javascript: Trigger 'change' eventlistener when updating <select> value

Note: Not using jQuery, before you mark this as a duplicate make sure other Q/A is pure JS.
I set my event listener like this, which works perfectly when triggered via html:
document.getElementById('activitySelector').addEventListener('change', function() {
console.log("I work triggered by html but not js")
}
I'm adding additional functionality where I change the select value via javascript, which works in that the html updates, but the eventListener is never triggered:
document.getElementById("activitySelector").value = interactiveType
To achieve what you want you should create the event manually and dispatch it. It's not difficult, as you could see here: http://www.2ality.com/2013/06/triggering-events.html?m=1
This is my initial solution. Just have the event handler trigger your code wrapped as a function. That way you can just call that same function when updating via javascript.
As #dfsq has pointed out this is just how it works. Manually triggering the event would probably take more code than this method:
// All code originally in eventListener now in function
function onActivityChange() {
console.log("I work triggered by html and js")
}
// Call above function from eventlistener
document.getElementById('activitySelector').addEventListener('change', onActivityChange)
// Trigger same function after updating value
document.getElementById("activitySelector").value = interactiveType
onActivityChange()

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.

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

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')

Intercept javascript event

Here's what I'm trying to do :
I have a page with some links. Most links have a function attached to them on the onclick event.
Now, I want to set a css class to some links and then whenever one of the links is clicked I want to execute a certain function - after it returns , I want the link to execute the onclick functions that were attached to it.
Is there a way to do what I want ? I'm using jQuery if it makes a difference.
Here's an attempt at an example :
$("#link").click(function1);
$("#link").click(function2);
$("#link").click(function(){
firstFunctionToBeCalled(function (){
// ok, now execute function1 and function2
});
}); // somehow this needs to be the first one that is called
function firstFunctionToBeCalled(callback){
// here some user input is expected so function1 and function2 must not get called
callback();
}
All this is because I'm asked to put some confirmation boxes (using boxy) for a lot of buttons and I really don't want to be going through every button.
If I understand you correctly, is this wat you wanted to do..
var originalEvent = page.onclick; //your actual onclick method
page.onclick = handleinLocal; //overrides this with your locaMethod
function handleinLocal()
{ ...your code...
originalEvent ();
// invoke original handler
}
I would use jQuery's unbind to remove any existing events, then bind a function that will orchestrate the events I want in the order I want them.
Both bind and unbind are in the jQuery docs on jquery.com and work like this...
$(".myClass").unbind("click"); // removes all clicks - you can also pass a specific function to unbind
$(".myClass").click(function() {
myFunctionA();
myFunctionB($(this).html()); // example of obtaining something related to the referrer
});
An ugly hack will be to use the mousedown or mouseup events. These will be called before the click event.
If you can add your event handler before the rest of handlers, you could try to use jQuery's stopImmediatePropagation

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