...
> My html have 2 frames...
That is the 'first sign of trouble'. Frames were always quirky
and problematic. More so as time goes by.
>..One is control frame which have a control
>applet loaded.Another frame's content will be insert a dynamically
>generated applet.But the dynamically generated applet can not get
>access to the control applet through it's static variable.How is that?
What browser? The very fact you would not mention the
browser (make + version), OS (make + version), and JRE
(make + version), indicates to me that you do not have much
experience 'wrestling with' applets in browsers, because..
>I found if the applet was not dynamically inserted to the dom
>tree,..
..besides that, there are no guarantees that applets in the
same page, different frames of the same page, different 'tabs',
or different browser instances, will share a VM (or not).
It is all up to the browser/VM combo.
(big trim...)
You spend more words describing the whole complex
situation, but I am going to ask something you did not
think to mention.
What is this all for? Or better still..
What do these applets do for the end user?
There may be an altogether better alternative to providing
this functionality, but it is important to understand the point
of it all.

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Andrew Thompson
http://www.athompson.info/andrew/