function Browser() {
		  var ua, s, i;
		
		  this.isIE    = false;
		  this.isNS    = false;
		  this.version = null;
		
		  ua = navigator.userAgent;
		
		  s = "MSIE";
		  if ((i = ua.indexOf(s)) >= 0) {
			this.isIE = true;
			this.version = parseFloat(ua.substr(i + s.length));
			return;
		  }
		
		  s = "Netscape6/";
		  if ((i = ua.indexOf(s)) >= 0) {
			this.isNS = true;
			this.version = parseFloat(ua.substr(i + s.length));
			return;
		  }
		
		  s = "Gecko";
		  if ((i = ua.indexOf(s)) >= 0) {
			this.isNS = true;
			this.version = 6.1;
			return;
		  }
		}

		var browser = new Browser();
		var dragObj = new Object();
		dragObj.zIndex = 0;
		
		function dragStart(event, id) {
		  var el;
		  var x, y;

		  if (id)
			dragObj.elNode = document.getElementById(id);
		  else {
			if (browser.isIE)
			  dragObj.elNode = window.event.srcElement;
			if (browser.isNS)
			  dragObj.elNode = event.target;
		
			if (dragObj.elNode.nodeType == 3)
			  dragObj.elNode = dragObj.elNode.parentNode;
		  }
		
		  if (browser.isIE) {
			x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
			y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
		  }
		  if (browser.isNS) {
			x = event.clientX + window.scrollX;
			y = event.clientY + window.scrollY;
		  }
		
		  dragObj.cursorStartX = x;
		  dragObj.cursorStartY = y;
		  dragObj.elStartLeft  = parseInt(dragObj.elNode.style.left, 10);
		  dragObj.elStartTop   = parseInt(dragObj.elNode.style.top,  10);
		
		  if (isNaN(dragObj.elStartLeft)) dragObj.elStartLeft = 0;
		  if (isNaN(dragObj.elStartTop))  dragObj.elStartTop  = 0;
		
		  dragObj.elNode.style.zIndex = ++dragObj.zIndex;
		
		  if (browser.isIE) {
			document.attachEvent("onmousemove", dragGo);
			document.attachEvent("onmouseup",   dragStop);
			window.event.cancelBubble = true;
			window.event.returnValue = false;
		  }
		  if (browser.isNS) {
			document.addEventListener("mousemove", dragGo,   true);
			document.addEventListener("mouseup",   dragStop, true);
			event.preventDefault();
		  }
		}

		function dragGo(event) {
		  var x, y;
		
		  if (browser.isIE) {
			x = window.event.clientX + document.documentElement.scrollLeft + document.body.scrollLeft;
			y = window.event.clientY + document.documentElement.scrollTop + document.body.scrollTop;
		  }
		  if (browser.isNS) {
			x = event.clientX + window.scrollX;
			y = event.clientY + window.scrollY;
		  }
		  dragObj.elNode.style.left = (dragObj.elStartLeft + x - dragObj.cursorStartX) + "px";
		  dragObj.elNode.style.top  = (dragObj.elStartTop  + y - dragObj.cursorStartY) + "px";
		
		  if (browser.isIE) {
			window.event.cancelBubble = true;
			window.event.returnValue = false;
		  }
		  if (browser.isNS)
			event.preventDefault();
		}

		function dragStop(event) {
		  if (browser.isIE) {
			document.detachEvent("onmousemove", dragGo);
			document.detachEvent("onmouseup",   dragStop);
		  }
		  if (browser.isNS) {
			document.removeEventListener("mousemove", dragGo,   true);
			document.removeEventListener("mouseup",   dragStop, true);
		  }
		}