var el = document.documentElement
, rfs = // for newer Webkit and Firefox
       el.requestFullScreen
    || el.webkitRequestFullScreen
    || el.mozRequestFullScreen
    || el.msRequestFullScreen
;
if(typeof rfs!="undefined" && rfs){
  rfs.call(el);
} else if(typeof window.ActiveXObject!="undefined"){
  // for Internet Explorer
  var wscript = new ActiveXObject("WScript.Shell");
  if (wscript!=null) {
     wscript.SendKeys("{F11}");
  }
}