var ieversion=99
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
 };

 var jswidth = window.innerWidth;
if (jswidth>1420 && ieversion>6) document.write("<div class='sidebar_l' id='sideBar_l'></div><div class='sidebar_r' id='sideBar_r'></div>");