Internet Explorer Vs Netscape

I designed some html pages. Now it is working fine with IE

I used some Java Scripts, Div tags and Frame and for font styles and all,

I created a .css file and for scripts I created .js file

But when I run the page in Netscape the Division which I defined as Hidden are also shown and the .css styles are omitted and the scripts are not working.

Pls. help me what I have to do?