function Is() {
  var agent = navigator.userAgent.toLowerCase();
  this.major = parseInt(navigator.appVersion);
  this.minor = parseFloat(navigator.appVersion);
  this.ns = ((agent.indexOf('mozilla')!=-1) && ((agent.indexOf('spoofer')==-1) && (agent.indexOf('compatible') == -1)));
  this.ns2 = (this.ns && (this.major == 3));
  this.ns3 = (this.ns && (this.major == 3));
  this.ns4b = (this.ns && (this.minor < 4.04));
  this.ns4 = (this.ns && (this.major >= 4));
  this.ie = (agent.indexOf("msie") != -1);
  this.ie3 = (this.ie && (this.major == 2));
  this.ie4 = (this.ie && (this.major >= 4));
  this.op3 = (agent.indexOf("opera") != -1);
  this.win = (agent.indexOf("win")!=-1);
  this.mac = (agent.indexOf("mac")!=-1);
  this.unix = (agent.indexOf("x11")!=-1);
}
var is = new Is();

function defineIE4() {
  w_Document = "document.all";
  d_Styles   = ".style";
  d_Layers   = ".tags('DIV')"
  d_Html     = ""
  l_Hide     = "hidden"
  l_Show     = "visible"
  w_Height   = 'height'
  w_Width    = 'width'
  w_Top      = 'top'
  w_Left     = 'left'
  w_resize   = 'resizable'
}

function defineNS4() {
  w_Document = "document";
  d_Html     = ".document"
  d_Styles   = "";
  d_Layer    = ".layers"
  l_Hide     = "hide"
  l_Show     = "show"
  if (is.major>3) {
    w_Height   = 'innerHeight'
    w_Width    = 'innerWidth'
  }
  else {
    w_Height   = 'height'
    w_Width    = 'width'
  }  
  w_Top      = 'screenY'
  w_Left     = 'screenX'
  w_resize   = 'resizable'
}

if(is.ns) {
  defineNS4()
} else if(is.ie) {
  defineIE4()
}