In jQuery, how to attach events to dynamic html el

Question

This question already has an answer here:

• Event binding on dynamically created elements? 23 answers

Suppose I have some jQuery code that attaches an event handler to all elements with class "myclass". For example:

$(function(){
    $(".myclass").click( function() {
        // do something
    });
});

And my html might be as follows:

<a class="myclass" href="#">test1</a>
<a class="myclass" href="#">test2</a>
<a class="myclass" href="#">test3</a>

That works with no problem. However, consider if the "myclass" elements were written to the page at some future time.

For example:

<a id="anchor1" href="#">create link dynamically</a>
<script type="text/javascript">
$(function(){
    $("#anchor1").click( function() {
        $("#anchor1").append('<a class="myclass" href="#">test4</a>');
    });
});
</script>

In this case, the "test4" link is created when a user clicks on a#anchor1.

The "test4" link does not have the click() handler associated with it, even though it has class="myclass".

Any idea how I can fix this?

Basically, I would like to write the click() handler once and have it apply to both content present at page load, and content brought in later via Ajax/DHTML.

Answer 1

Sometimes doing this (the top-voted answer) is not always enough:

$('body').on('click', 'a.myclass', function() {
    // do something
});

This can be an issue because of the order event handlers are fired. If you find yourself doing this, but it is causing issues because of the order in which it is handled.. You can always wrap that into a function, that when called "refreshes" the listener.

For example:

function RefreshSomeEventListener() {
    // Remove handler from existing elements
    $("#wrapper .specific-selector").off(); 

    // Re-add event handler for all matching elements
    $("#wrapper .specific-selector").on("click", function() {
        // Handle event.
    }
}

Because it is a function, whenever I set up my listener this way, I typically call it on document ready:

$(document).ready(function() {
    // Other ready commands / code

    // Call our function to setup initial listening
    RefreshSomeEventListener();
});

Then, whenever you add some dynamically added element, call that method again:

function SomeMethodThatAddsElement() {
    // Some code / AJAX / whatever.. Adding element dynamically

    // Refresh our listener, so the new element is taken into account
    RefreshSomeEventListener();
}

Hopefully this helps!

Regards,

Answer 2

You can bind a single click event to a page for all elements, no matter if they are already on that page or if they will arrive at some future time, like that:

$(document).bind('click', function (e) {
   var target = $(e.target);
   if (target.is('.myclass')) {
      e.preventDefault(); // if you want to cancel the event flow
      // do something
   } else if (target.is('.myotherclass')) {
      e.preventDefault();
      // do something else
   }
});

Been using it for a while. Works like a charm.

In jQuery 1.7 and later, it is recommended to use .on() in place of bind or any other event delegation method, but .bind() still works.

Answer 3

If you're adding a pile of anchors to the DOM, look into event delegation instead.

Here's a simple example:

$('#somecontainer').click(function(e) {   
  var $target = $(e.target);   
  if ($target.hasClass("myclass")) {
    // do something
  }
});

Answer 4

If your on jQuery 1.3+ then use .live()

Binds a handler to an event (like click) for all current - and future - matched element. Can also bind custom events.

Answer 5

I am adding a new answer to reflect changes in later jQuery releases. The .live() method is deprecated as of jQuery 1.7.

From http://api.jquery.com/live/

As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers. Users of older versions of jQuery should use .delegate() in preference to .live().

For jQuery 1.7+ you can attach an event handler to a parent element using .on(), and pass the a selector combined with 'myclass' as an argument.

See http://api.jquery.com/on/

So instead of...

$(".myclass").click( function() {
    // do something
});

You can write...

$('body').on('click', 'a.myclass', function() {
    // do something
});

This will work for all a tags with 'myclass' in the body, whether already present or dynamically added later.

The body tag is used here as the example had no closer static surrounding tag, but any parent tag that exists when the .on method call occurs will work. For instance a ul tag for a list which will have dynamic elements added would look like this:

$('ul').on('click', 'li', function() {
    alert( $(this).text() );
});

As long as the ul tag exists this will work (no li elements need exist yet).

Answer 6

You want to use the live() function. See the docs.

For example:

$("#anchor1").live("click", function() {
    $("#anchor1").append('<a class="myclass" href="#">test4</a>');
});