Ahh that makes sense. Thanks for taking the time :)
Karl Rudd wrote:
>
> The ! operator does a "binary invert", returning either "true" or "false".
> So:
>
> true == !false
> false == !true
>
> So:
>
> false == !!false
> true == !!true
>
> Combine that with what JavaScript considers "false" and you end up
> with something like this:
>
> // Test to see whether something is "null" or 0 (zero) or
> "undefined" or "false"
> var something = doSomething();
> if ( !something )
> doSomethingElse();
>
> Anything that is NOT "null" or 0 (zero) or "undefined" or "false", is
> considered "true".
>
> Going back to the "!!s[k]". The problem is that the value of s[k]
> might not be a boolean "true" or "false", so we need to convert it to
> one.
>
> So we "!" it first and that converts it to a boolean, though if it was
> a "true" value it's now "false", and vice-versa. So we "!" it again
> and it comes out the "correct" way.
>
> Karl Rudd
>
> On 3/14/07, Daemach <[EMAIL PROTECTED]> wrote:
>>
>> What does the !! do?
>>
>>
>> Dan G. Switzer, II wrote:
>> >
>> >>Please add:
>> >>
>> >> StructKeyExists: function(s,k){
>> >> for(var n in s){
>> >> if (n == k) return true;
>> >> }
>> >> return false;
>> >> },
>> >>
>> >>
>> >>Shall we post additions and updates here?
>> >
>> > This would be much more efficient:
>> >
>> > StructKeyExists: function(s,k){
>> > return !!s[k];
>> > },
>> >
>> > However, it's also important to remember that a ColdFusion "structure"
>> > isn't
>> > the exact same thing as a JavaScript Object.
>> >
>> > -Dan
>> >
>> >
>> > _______________________________________________
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>> > http://jquery.com/discuss/
>> >
>> >
>>
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>>
>>
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>
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