code on aspx page for different browsers(to call style sheet)

code on  aspx page for different browsers(to call style sheet): internet explorer . firefox.

 when we r seeting our design page then we use a code in aspx page for browser compatiable code , different for different browsers .

for seeting design on page .

if it is firefox , then inside firefox stylesheet call up.

if it is internet explorer , then inside internet explorer stylesheet call up

 

What is that code? i need?? plz help

 

 
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