Re: Two Questions.
Ben Curtis <[email protected]> Thu, 3 Dec 2009 08:26:23 -0800
| Newsgroups | gmane.comp.web.dom.wdf |
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| Message-ID | <[email protected]> |
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On Dec 3, 2009, at 4:24 AM, Srinivasan wrote:
> 1. what is the difference between
> function f() {
>
> }
> and
> var f = function() {
>
> }
I'm really bad with that. But I can tell you this: if you assign the
function to a variable (your second example) *always* scope it locally
with "var" or you will get unexpected results. Example (the "window."
prefixes are just to make the example clear -- it operates the same
without them):
<html>
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
<script type="text/javascript">
function basic () { alert('I am part of the window object!'); }
function nesting1 () {
function basic () { alert('I am nested!'); }
basic();
}
window.basic(); // alerts 'I am part of the window object!'
nesting1(); // alerts 'I am nested!'
window.basic(); // properly alerts 'I am part of the window
object!'
overridden = function () { alert('I am part of the window
object!'); }
function nesting2 () {
overridden = function () { alert('I am nested!'); }
overridden();
}
window.overridden(); // alerts 'I am part of the window object!'
nesting2(); // alerts 'I am nested!'
window.overridden(); // uh oh -- now alerts 'I am nested!'
var scoped = function () { alert('I am part of the window
object!'); }
function nesting3 () {
var scoped = function () { alert('I am nested!'); }
scoped();
}
window.scoped(); // alerts 'I am part of the window object!'
nesting3(); // alerts 'I am nested!'
window.scoped(); // properly alerts 'I am part of the window
object!'
</script>
</head>
<body>
</body>
</html>
--
Ben Curtis : webwright
bivia : a personal web studio
http://www.bivia.com/
--tkI46bXr6ERQKvXj5D019UmQB2dK3hw2hAzbjBE
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<p><br>
On Dec 3, 2009, at 4:24 AM, Srinivasan wrote:<br>
<br>
> 1. what is the difference between<br>
> function f() {<br>
><br>
> }<br>
> and<br>
> var f = function() {<br>
><br>
> }<br>
<br>
I'm really bad with that. But I can tell you this: if you assign the <br>
function to a variable (your second example) *always* scope it locally <br>
with "var" or you will get unexpected results. Example (the "window." <br>
prefixes are just to make the example clear -- it operates the same <br>
without them):<br>
<br>
<html><br>
<head><br>
<title></title><br>
<meta http-equiv="<wbr>Content-Type" content="text/<wbr>html;charset=<wbr>UTF-8" /><br>
<script type="text/javascri<wbr>pt"><br>
function basic () { alert('I am part of the window object!'); }<br>
function nesting1 () {<br>
function basic () { alert('I am nested!'); }<br>
basic();<br>
}<br>
window.basic(<wbr>); // alerts 'I am part of the window object!'<br>
nesting1(); // alerts 'I am nested!'<br>
window.basic(<wbr>); // properly alerts 'I am part of the window <br>
object!'<br>
<br>
overridden = function () { alert('I am part of the window <br>
object!'); }<br>
function nesting2 () {<br>
overridden = function () { alert('I am nested!'); }<br>
overridden()<wbr>;<br>
}<br>
window.overridden(<wbr>); // alerts 'I am part of the window object!'<br>
nesting2(); // alerts 'I am nested!'<br>
window.overridden(<wbr>); // uh oh -- now alerts 'I am nested!'<br>
<br>
var scoped = function () { alert('I am part of the window <br>
object!'); }<br>
function nesting3 () {<br>
var scoped = function () { alert('I am nested!'); }<br>
scoped();<br>
}<br>
window.scoped(<wbr>); // alerts 'I am part of the window object!'<br>
nesting3(); // alerts 'I am nested!'<br>
window.scoped(<wbr>); // properly alerts 'I am part of the window <br>
object!'<br>
</script><br>
</head><br>
<body><br>
<br>
</body><br>
</html><br>
<br>
-- <br>
<br>
Ben Curtis : webwright<br>
bivia : a personal web studio<br>
<a href="http://www.bivia.com/">http://www.bivia.<wbr>com/</a><br>
<br>
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