Subj : Re: How to use scripts to create persistent objects?
To   : netscape.public.mozilla.jseng
From : wayne
Date : Mon Sep 13 2004 07:03 pm

After days of beating my head against the wall thinking I was using
the library incorrectly, it turned out to be a unrelated, bonehead
mistake on my part.

I apologize if anyone wasted any time on this posting.

Sincerely,

Wayne

wayne@lamontmarketing.com (Wayne) wrote in message news:<eed35ca2.0409130641.433f137@posting.google.com>...
> According to the JavaScript C Engine Embedder's Guide:
> 
> "NOTE: You can also use scripts to create persistent objects, too."
> 
> However, I am unable to figure out how to accomplish this (and was
> unable to find previous newsgroup postings explaining this process
> after doing a *very* extensive search).
> 
> JS_EvaluateScript() on the following JS:
> 
> var m = new MyObject( 5 );
> 
> function MyObject( num )
> {
>   this.num = num;
> }
> 
> alert( 'm.num = ' + m.num );
> 
> document.write( '<div id="m1"></div>' );
> var o = document.all[ "m1" ];
> o.m = m;
> alert( 'o.m.num = ' + o.m.num );
> var p = document.all[ "m1" ];
> alert( 'p.m.num = ' + p.m.num );
> 
> Each alert( X.m.num ) prints "5" as expected. Then, we immediately do
> another JS_EvaluateScript() (same JSContext & Runtime) on the
> following JS:
> 
> var q = document.all[ "m1" ];
> alert( 'q.m.num = ' + q.m.num );
> 
> but instead of printing "5", we get "TypeError: q.m has no properties
> line 0".
> 
> It may not be possible to answer without knowing all the C code behind
> this, but why does the technique of setting a property in the object
> held in the document.all array at "m1" appear to work within one
> script execution, but not subsequent script executions using
> essentially the same code? (By the way, replacing the second JS code
> segment with "alert( 'm.num = ' + m.num );" does output "5".)
> 
> Any help and guidance would be most appreciated.
> 
> Thank you,
> 
> Wayne

.