Down and dirty IE detection script. Works on IE11.

ie.js

function getInternetExplorerVersion() {
      var rv = -1;
      if (navigator.appName == 'Microsoft Internet Explorer')
      {
        var ua = navigator.userAgent;
        var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
        if (re.exec(ua) != null)
          rv = parseFloat( RegExp.$1 );
      }
      else if (navigator.appName == 'Netscape')
      {
        var ua = navigator.userAgent;
        var re  = new RegExp("Trident/.*rv:([0-9]{1,}[\.0-9]{0,})");
        if (re.exec(ua) != null)
          rv = parseFloat( RegExp.$1 );
      }
      return rv;
    }

    var browser = getInternetExplorerVersion();
    if (browser > 0) {
      docElement.className = 'ie';
    }