what is the relative javascript for Netscape 6?

[JasonXie]

My script can work fine on IE4 or 5 and Netscape 4.7. Since Netscape6 ignores
"Layer" and support "IFrame", I have to transfer the script to suit Netscape6.
What I am confusing is that even through Netscape 6 supports "IFrame", but why the
below script can't work on Netscape6 ?

temp=document.getElementById("myIFrame&quot.document.body.innerHTML

Does IFrame in Netscape6 have not "document.body.innerHTML" property?

What I am going to do is :
1,Dynamically import an external file to "myIFrame" by
document.getElementById("myIFrame&quot.src = myexternalfile
(myexternalfile is a variable cotaining such as "myfile.html&quot
2,Get the innerHTML of "myIFrame" and pass them to a DIV element
The script for this is the below but doesn't work on Netscape 6.
document.getElementById("myDiv&quot.innerHTML =
document.getElementById("myIFrame&quot.document.body.innerHTML

Please tell me how to correct the scripts above or redirect me to a right place to find
the relative documentation for these sort of questions.