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OK guys this is intreting,

I'm testing this page

http://static.nemesisdesign.net/demos/ie8-strange/test.html

on IE8 / windows XP.

This is the code:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
    <meta charset="UTF-8" />
    <meta http-equiv="content-language" content="en">
    <title>Test</title>
</head>
<body>
<div id="thisgivesmeanerror">test</div>
<script>
    thisgivesmeanerror = 'test';
    alert('this alert won\'t be fired on my IE8, what about yours?');
</script>
</body>
</html>

If I open this page with IE8 I get an error. If I change the code of the script to:

<script>
    // note that I added var prefix
    var thisgivesmeanerror = 'test';
    alert('this alert won\'t be fired on my IE8, what about yours?');
</script>

It works fine. This happens only on IE 7/8, didn't test it on IE6.

What do you think? Does it happen to you also? Or is it just my browser that has gone crazy?

Addition

You're saying that is just not using the var prefix that cause the error? I'm sorry guys but you're wrong, you didn't take time to test the code.

I uploaded a test2 page http://static.nemesisdesign.net/demos/ie8-strange/test2.html with the follwing cocde

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
    <meta charset="UTF-8" />
    <meta http-equiv="content-language" content="en">
    <title>Test 2</title>
</head>
<body>
<div id="thisgivesmeanerror">test</div>
<script>
    thisdoesntgiveanyerror = 'test';
    alert('This alert will be fired correcly');
</script>
</body>
</html>

That works fine.

So what is actually causing the error? The variable name without the var prefix having the same name as the ID of the DIV element.

Isn't this strange?

nemesisdesign
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4 Answers4

2

May be the answers to this SO-question can help?

Community
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KooiInc
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1

You should always precede your variable declarations with var to specify their scope or you might observe inconsistent behavior between different browsers.

Darin Dimitrov
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  • Yes, the scope of variable is very important. If you don't use `var` when declaring your variable IE8 might use some other variable with the same name like in your example the id of the div. – Darin Dimitrov Nov 27 '10 at 11:27
0

I'd say the JavaScript interpreter in IE is slightly stricter than on FireFox and others, meaning the script returns an error when it comes to the variable definition line. Putting var in will ensure it actually is a variable.

It's very good practice to declare all your variables with var

James

EDIT

I can't get to IE at the moment, but I can recommend you change your <script> tag to <script type="text/javascript">.

Bojangles
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0

use var to declare variables instead of just plugging their name

Ali Tarhini
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