Get Internet Explorer Version

check_ie.js

  getInternetExplorerVersion: function(){
    // Returns the version of Internet Explorer or a -1
    // (indicating the use of another browser).
    var rv = -1; // Return value assumes failure.
    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 );
    }
    return rv;
  },