<html> <style> p { border:1px solid red; max-width:30em; width:expression( document.body.clientWidth > (500/12) * parseInt(document.body.currentStyle.fontSize)? "30em": "auto" ); } </style> <body> <p> [alot of text] </p> </body> </html>reference : http://www.svendtofte.com/code/max_width_in_ie/