Why does window.onload work while document.onload doesn't?
Question
Can anyone tell me why the following page doesn't trigger an alert when it loads? If I use window.onload instead of document.onload it works. Why is there this difference?
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
document.onload = function() {
alert('Test');
}
</script>
</head>
<body>
</body>
</html>
2 answers
solution1
8 ACCPTED 2011-02-27 20:28:49
The simplest answer is that it just wasn't designed that way. The browser executes the function attached to window.onload at the " end of the document loading process ". It does not attempt to execute a function attached to document.onload .
You could assign a function to document.onload but the browser will not do anything special with it.
Some things to keep in mind (assuming you've just assigned a function to one or the other of window.onload or document.onload ):
-
window.onload === onload -
window.onload !== document.onload -
window !== document
solution2
1 2011-02-27 20:18:21
The event handler is onload not document.onload . It hangs directly off the window object (which is the default object).
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