Asp .net drop down width

I have a drop开发者_StackOverflow社区 down. I want the drop down to be of 200 px width but when some one clicks on the drop down button,(the contents which come below the drop down )should be of a greater width(say 300 px or self adjusting width based on text). Is that possible ?

This is the default behaviour in Firefox. I think its not possible in Internet Explorer.

EDIT: redirected from google to Stackoverflow, look here