Difference between $(window).load() and $(document).ready() functions

Asked 3/1, 2011 at 12:22 Answered 5/9, 2018 at 11:28

261

What is the difference between $(window).load(function() {}) and $(document).ready(function() {}) in jQuery?

Corral answered 3/1, 2011 at 12:22 Comment(1)

Note that in jQuey 3.x there is no $(window).load(). Use $(window).on('load', function(){}); instead. – Fasano 27/8, 2020 at 15:14

297

document.ready is a jQuery event, it runs when the DOM is ready, e.g. all elements are there to be found/used, but not necessarily all content.
window.onload fires later (or at the same time in the worst/failing cases) when images and such are loaded, so if you're using image dimensions for example, you often want to use this instead.

Hyper answered 3/1, 2011 at 12:36 Comment(9)

shorthand for $(document).ready(function(){}) is $(function(){}) and another important difference from the window.load is that it will run on ALL future calls of the function, even after the initial DOMready. – Piperidine 3/4, 2014 at 21:29

are we to infer that onload is the same as load? – Acker 21/1, 2016 at 5:24

@dbliss Yes I believe onload is shorthand for $(window).on('load'). Both referencing the load event. – Overwrought 19/3, 2016 at 9:10

@MichaelButler - What do you mean with it will run on ALL future calls of the function? – Taimi 22/5, 2016 at 15:17

@MichaelButler's comment is partially wrong. $(document).ready(function(){}) is only executed once, when the DOM is ready. There is no such thing as "future calls". – Sergio 14/8, 2016 at 19:36

@Doug S., sorry but you are wrong or misunderstood here. See the jquery api documentation: "If .ready() is called after the DOM has been initialized, the new handler passed in will be executed immediately." my comment stands correct. We're talking about the ready function notan arbitrary specific callback handler. – Piperidine 15/8, 2016 at 23:6

@MichaelButler: You need to be more clear in your comment. 1) You're talking about the USER executing more $(document).ready code after the DOM is ready. That's such a small use case that it probably wasn't worth confusing everyone with mentioning it. 2) The ENVIRONMENT only calls $(document).ready(f‌unction(){}) once, when the DOM is ready. If the user, for some reason, executes more $(document).ready after the DOM is ready, then yes, it will be executed immediately. – Sergio 16/8, 2016 at 3:53

@DougS I think you should delete your comments, you're just digging yourself into a hole now. – Piperidine 16/8, 2016 at 13:36

I beg to differ, Michael. Let's just leave it at this and not degrade into useless comments. At least the confused people now have their answer. – Sergio 16/8, 2016 at 17:57

$(document).ready(function() {
 // executes when HTML-Document is loaded and DOM is ready
 alert("document is ready");
});


$(window).load(function() {
 // executes when complete page is fully loaded, including all frames, objects and images
 alert("window is loaded");
});

Monosyllabic answered 19/11, 2013 at 9:43 Comment(2)

Will 'load' execute again, if e.g. an Ajax request finished after the user started it by clicking a button? – Babar 5/3, 2023 at 19:15

@Babar no! – Monosyllabic 7/3, 2023 at 7:22

The $(window).load() is NOT available in jQuery 3.0

$( window ).load(function() {
        // Handler for .load() called.
});

To get around it, you can use it as an "Event Handler Attachment"

$( window ).on("load", function() {
        // Handler for .load() called.
});

Suddenly answered 5/9, 2018 at 11:28 Comment(0)

The difference are:

$(document).ready(function() { is jQuery event that is fired when DOM is loaded, so it’s fired when the document structure is ready.

$(window).load() event is fired after whole content is loaded.

Flunkey answered 5/4, 2013 at 5:50 Comment(0)

<html>
<head>
    <script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
    <script>
    $( document ).ready(function() {
        alert( "document loaded" );
    });

    $( window ).load(function() {
        alert( "window loaded" );
    });
    </script>
</head>
<body>
    <iframe src="http://stackoverflow.com"></iframe>
</body>
</html>

window.load will be triggered after all the iframe content is loaded

Govan answered 25/11, 2013 at 6:44 Comment(0)

$(document).ready happens when all the elements are present in the DOM, but not necessarily all content.

$(document).ready(function() {
    alert("document is ready");
});

window.onload or $(window).load() happens after all the content resources (images, etc) have been loaded.

$(window).load(function() {
    alert("window is loaded");
});

Birddog answered 31/1, 2017 at 10:54 Comment(0)

From jquery prospective - it's just adding load/onload event to window and document. Check this out:

window.onload vs document.onload

Cosetta answered 3/1, 2011 at 12:26 Comment(0)

I think the $(window).load event is not supported by JQuery 3.x

Younglove answered 22/10, 2017 at 23:56 Comment(2)

As per the documentation the $(window).load event was removed in JQuery 3.0 – Einkorn 23/10, 2017 at 0:5

This is correct. In order to get around it, you can use it as an "Event Handler Attachment": $( window ).on("load", function() { // Handler for .load() called. }); – Suddenly 5/9, 2018 at 11:21

According to DOM Level 2 Events, the load event is supposed to fire on document, not on window. However, load is implemented on window in all browsers for backwards compatibility.

Ratter answered 17/12, 2012 at 17:18 Comment(0)

document.ready (jQuery) document.ready will execute right after the HTML document is loaded property, and the DOM is ready.

DOM: The Document Object Model (DOM) is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents.

$(document).ready(function()
{
   // executes when HTML-Document is loaded and DOM is ready
   alert("(document).ready was called - document is ready!");
});

window.load (Built-in JavaScript) The window.load however will wait for the page to be fully loaded, this includes inner frames, images etc. * window.load is a built-in JavaScript method, it is known to have some quirks in old browsers (IE6, IE8, old FF and Opera versions) but will generally work in all of them.

window.load can be used in the body's onload event like this (but I would strongly suggest you avoid mixing code like this in the HTML, as it is a source for confusion later on):

$(window).load(function() 
{
   // executes when complete page is fully loaded, including all frames, objects and images
   alert("(window).load was called - window is loaded!");
});

Moleskin answered 7/2, 2018 at 5:58 Comment(0)

$(window).load is an event that fires when the DOM and all the content (everything) on the page is fully loaded like CSS, images and frames. One best example is if we want to get the actual image size or to get the details of anything we use it.

$(document).ready() indicates that code in it need to be executed once the DOM got loaded and ready to be manipulated by script. It won't wait for the images to load for executing the jQuery script.

<script type = "text/javascript">
    //$(window).load was deprecated in 1.8, and removed in jquery 3.0
    // $(window).load(function() {
    //     alert("$(window).load fired");
    // });

    $(document).ready(function() {
        alert("$(document).ready fired");
    });
</script>

$(window).load fired after the $(document).ready().

$(window).load was deprecated in 1.8, and removed in jquery 3.0

Tarryn answered 14/6, 2018 at 7:12 Comment(0)

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