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Re: Global variable is deletable?

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From JJ <jaejunks@nah.meh>
Newsgroups comp.lang.javascript
Subject Re: Global variable is deletable?
Date Mon, 7 Jan 2013 15:36:17 +0000 (UTC)
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Stefan Weiss <krewecherl@gmail.com> wrote:
> On 2013-01-07 10:21, Thomas Li wrote:
>> Hi, I'm fresh in Javascript. From the book "Javascript, the
>> definitive guide", the global variable should be nondeletable,
>> however when I test it in IE, it is deletable, anything wrong? 
>> Steps:
>> 1. Open IE 9
>> 2. Press F12 and select Console panel
>> 3. Var temp = 1;
>>    delete temp;
>> 4. it returns true and when I enter temp, it says "temp is undefined"
> 
> When you enter something in the console, it gets evaluated with eval().
> Variables created from eval()ed code don't have the DontDelete flag 
set.
> 
> Details:
> http://perfectionkills.com/understanding-delete/#firebug_confusion
> 
> 
> - stefan

I'd toss that book.

<!DOCTYPE html>
<html>
<body>
<script>
console.log(typeof abc); //undefined
abc=123;
console.log(typeof abc); //number
delete abc;
console.log(typeof abc); //undefined
</script>
</body>
</html>

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Thread

Global variable is deletable? Thomas Li <cooooooder@gmail.com> - 2013-01-07 01:21 -0800
  Re: Global variable is deletable? Stefan Weiss <krewecherl@gmail.com> - 2013-01-07 11:24 +0100
    Re: Global variable is deletable? JJ <jaejunks@nah.meh> - 2013-01-07 15:36 +0000
      Re: Global variable is deletable? Scott Sauyet <scott.sauyet@gmail.com> - 2013-01-07 07:50 -0800
    Re: Global variable is deletable? Thomas Li <cooooooder@gmail.com> - 2013-01-07 22:08 -0800
  Re: Global variable is deletable? dann90038@gmail.com - 2013-01-07 13:25 -0800
    Re: Global variable is deletable? Thomas Li <cooooooder@gmail.com> - 2013-01-07 21:48 -0800

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