if (/MSIE (\d+\.\d+);/.test(navigator.userAgent)) ( //test for MSIE x.x; var ieversion=new Number(RegExp.$1) // capture x.x portion and store as a number if (ieversion>=8) document.write("You're using IE8 or above") else if (ieversion>=7) document.write("You're using IE7.x") else if (ieversion>=6) document.write("You're using IE6.x") else if (ieversion>=5) document.write("You're using IE5.x") ) else document.write("n/a") Ссылка