[thelist] does JavaScript have an equivalent to IsDefined()?

Sarah poohbear at designshift.com
Mon Sep 22 15:49:46 CDT 2003


> ><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
> > From: Sarah
> >
> > More ASP/JavaScript woes :) Is there a JavaScript
> > equivalent to the ColdFusion IsDefined() function? I
> > would like to be able to test to see if a variable is
> > defined in the querystring, but none of the methods I
> > have tried has worked. I have tried:
> >
> > if (Request.QueryString('id') == null) //...
> > if (Request.QueryString('id') == undefined) //...
> > if (Request.QueryString('id') == 'undefined') //...
> > if (typeof Request.QueryString('id') == undefined) //...
> > if (typeof Request.QueryString('id') == 'undefined') //...
> ><><><><><><><><><><><><><><><><><><><><><><><><><><><><><
>
>is this client-side or server-side?
>
>either way, what does Request.QueryString('id') return?

Jeff,

This is server-side. When I do Response.Write(Request.QueryString('id')), I 
get undefined, but if I try to compare to undefined, i.e...
   if (Request.QueryString('id') != undefined) { }
...the code executes (incorrectly), and an error is thrown because the 
query that follows craps out on the undefined value. *Very* perplexing!

(BTW, I've tried comparing to both undefined and 'undefined', same results 
with each - which is correct?)

Thanks,

Sarah



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