Re: How to know that a window is still open

["John Ray" <jray@community.net>]

> Few days ago I asked how to recognize that a given window is
> the topmost window

There have been a few posts in reply to this. Here's mine.

      Given the following:

> Weird.  The following works for me (I'm using Windows
> 95, BTW):
> 
> <SCRIPT>
** > if (window.name == "")
> 	alert ("top level window")


     and the following:


> >Off the top of my head: If you open the window and
> >pass it a name, like this:
> >
> >        window.open ("blah.html", "win1");
> >
> >then it will have a name.  You can test for the name
> >with
> >
** > >        if (window.name !="")
> >                 you're in the top window
> >
> >But, it doesn't work. I tried to display window.name
> >(exactly in this example window.win1) with alert and
> >always I'v got '<undefined>' value.


I wouldn't trust versions of Netscape across all platforms
to act the same. Some might return "", or undefined, or
null in some cases. Changing the marked line of the
script in the first example to:

    if (window.name+"" == "")

and the marked line of the second example to:

    if (window.name+"" !="")

might provide better compatibility across platforms. To convert any 
unexpected <undefined> and null to usable values I use the following:

for string (as above)

    string+""   for compares and     string+=""     for assignment

for numeric

     value+0     for compares and     value=+0     for assignment.

If  I need to compare a numeric value against its string counterpart, 
temporarally express it as a string, or need to use it with indexOf () 
and do not want to change the original value I will use:

    value+""   

 or if  I want it changed to a string I'll use

      value+="";

And last but not least. The same as above but for numeric values I 
use:

for compares:

     string*1   If  I know the string will equate to a number.
     parseInt(string)  or  parseFloat(string)   If I'm not sure.

for assignment:

     string*=1   If I know the string will equate to a number.
     string=parseInt(string)  or  string=parseFloat(string)  If I'm not sure.

     Note: 'string' in the last example becomes numeric. I'm just 
     reusing the vaiable 'string' rather than creating a new one.

I'm sure everyone knows the * verses + in the above example is due to 
JavaScript equating + to concantinate for expressions invoving a 
string variable or literal.

I gotta stop drinking so much Diet Coke. I write too much.

John
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