Does the jQuery $(window).load(); event not fire on pages without a declaration? (...in a chrome extension content script)

Question

I'm working on a Google Chrome extension that manipulates a webpage, but after it is either partially loaded (the DOM) or fully loaded (with images).

It seems that many sites nowadays use the

<!DOCTYPE html>

declaration, or some variation of it, but many others do not. The question is mainly about HTML doctypes...I'm not sure about the others.

Is it safe to assume that if a webpage does not have the DOCTYPE declaration, then $(window).load(); will not be fired?

In the beginning I was using $(document).ready(); (for when the DOM is loaded), but later switched to $(window).load(); (to let the images load too).

The thing is, now $(window).load(); does not seem to work if there is no DOCTYPE. $(document).ready(); seems to work on all pages, regardless of whether a DOCTYPE is declared or not.

Maybe this can be useful for others with this same issue. I searched a bit and didn't find a decisive answer. It seems that I will end up using something like this:

if (window.document.doctype != null) {$(window).load(checkEntries);}
if (window.document.doctype == null) {$(document).ready(checkEntries);}

I guess my question is... Is this normal to have to check for the DOCTYPE to know which event to use? Or am I missing something here?

Basically, why does $(window).load(); seem not to fire if there's no DOCTYPE declaration?

LukeGT · Accepted Answer

Basically, you shouldn't be using $(window).load(), since it's not fully supported. If you really need it, then your solution above is the best you can do. The jQuery page sums up the caveats nicely:

Caveats of the load event when used with images

A common challenge developers attempt to solve using the .load() shortcut is to execute a function when an image (or collection of images) have completely loaded. There are several known caveats with this that should be noted. These are:

It doesn't work consistently nor reliably cross-browser

It doesn't fire correctly in WebKit if the image src is set to the same src as before

It doesn't correctly bubble up the DOM tree

Can cease to fire for images that already live in the browser's cache

URL: http://api.jquery.com/load-event/

Does the jQuery $(window).load(); event not fire on pages without a <!DOCTYPE> declaration? (...in a chrome extension content script)

Tags:

javascript

jquery

events

doctype

google-chrome-extension

theMaxx

1 Answers

LukeGT

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