function Browser()
 {
  var version = parseInt(navigator.appVersion);
   var agent = navigator.userAgent.toLowerCase(); 
   this.win = ((agent.indexOf("win")!=-1) || (agent.indexOf("16bit")!=-1));
   this.mac = (agent.indexOf("mac")!=-1); 
    this.ie = (navigator.appName == "Microsoft Internet Explorer");
    this.ns = (navigator.appName == "Netscape"); 
    this.ie4up = (this.ie && (version >= 4)); 
    this.ns4up = (this.ns && (version >= 4)); 
    this.dom = document.getElementById; 
    this.ie4Layer = (document.all); 
    this.ns4Layer = (document.layers && !this.dom);
    if(this.ns) 
    { 
        this.getCanvasWidth = function() {return innerWidth;}; 
        this.getCanvasHeight = function() {return innerHeight;};
         this.getWindowWidth = function() {return outerWidth;}; 
         this.getWindowHeight = function() {return outerHeight;}; 
         this.getScreenWidth = function() {return screen.width;}; 
         this.getScreenHeight = function() {return screen.height;}; 
         this.getMinX = function() {return(pageXOffset);}; 
         this.getMinY = function() {return(pageYOffset);};
          this.getMaxX = function() {return(pageXOffset+innerWidth);};
           this.getMaxY = function() {return(pageYOffset+innerHeight);};
   } 
   else if(this.ie)
    { 
        this.getCanvasWidth = function() {return document.body.clientWidth;}; 
        this.getCanvasHeight = function() {return document.body.clientHeight;};
         this.getScreenWidth = function() {return screen.width;}; 
         this.getScreenHeight = function() {return screen.height;}; 
         this.getMinX = function() {return(document.body.scrollLeft);};
          this.getMinY = function() {return(document.body.scrollTop);}; 
          this.getMaxX = function() {return(document.body.scrollLeft+document.body.clientWidth);};
           this.getMaxY = function() {return(document.body.scrollTop+document.body.clientHeight);}; 
     }
   return (this);
 }; 
browser = new Browser();