var DL_isIE = (document.all) ? true : false;
var DL_isDOM = (document.getElementById) ? true : false;
var DL_isNS4 = (document.layers) ? true : false;
var DL_isIE4 = DL_isIE && !DL_isDOM;
var DL_isMac = (navigator.appVersion.indexOf("Mac") != -1);
var DL_isIE4M = DL_isIE4 && DL_isMac;
  
var DL_TheWindowHeight = DL_isIE ? document.documentElement.clientHeight : window.innerHeight;
var DL_TheWindowWidth  = DL_isIE ? document.documentElement.clientWidth  : window.innerWidth;