function Browser() {
		
		  var ua, s, i;
		
		  this.isIE    = false;
		  this.isNS    = false;
		
		  ua = navigator.userAgent;
		
		  s = "MSIE";
		  if ((i = ua.indexOf(s)) >= 0) {
		    this.isIE = true;
		    return;
		  }
		
		  this.isNS = true;

		}
		
		var browser = new Browser();
		
		// Global object to hold drag information.
		
		var dragObj = new Object();
		
		var cual;
		
		function dragStart(cualx, event, idmensaje) {
		
		  var el;
		  var x, y;
		
		  cual=cualx;
		  
		  // If an element id was given, find it. Otherwise use the element being
		  // clicked on.

		  dragObj.elNode = document.getElementById('ventana' + idmensaje); 
		  dragObj.elStartZIndex = dragObj.elNode.style.zIndex;	
		  
		  
		  if (browser.isIE) {
			dragObj.elNode.style.filter = "alpha(opacity=70);"; 
		  } else {
		  	dragObj.elStartOpacity = dragObj.elNode.style.opacity;
		  	if (dragObj.elStartOpacity=="") {dragObj.elStartOpacity=1;}
		  	dragObj.elNode.style.opacity = dragObj.elStartOpacity - 0.2;
		  }
		  dragObj.elNode.style.zIndex= "99999";
		
		  // Get cursor position with respect to the page.
		
		  if (browser.isIE) {
		    x = window.event.clientX + document.documentElement.scrollLeft
		      + document.body.scrollLeft + dragObj.elNode.parentNode.style.left;
		    y = window.event.clientY + document.documentElement.scrollTop
		      + document.body.scrollTop + dragObj.elNode.parentNode.style.top;
		  }
		  if (browser.isNS) {
		    x = event.clientX + window.scrollX + dragObj.elNode.parentNode.style.left;
		    y = event.clientY + window.scrollY + dragObj.elNode.parentNode.style.top;
		  }
		
		  // Save starting positions of cursor and element.
		  
		  dragObj.cursorStartX = x;
		  dragObj.cursorStartY = y;
		  
		  if (cual==0) {
			  dragObj.elStartLeft  = parseInt(dragObj.elNode.style.left, 10);
			  dragObj.elStartTop   = parseInt(dragObj.elNode.style.top,  10);	 
		  }
		  if (cual==1) {
		  	dragObj.elStartWidth  = parseInt(dragObj.elNode.style.width, 10);
		  }
		  
		  
		  if (isNaN(dragObj.elStartLeft)) dragObj.elStartLeft = 0;
		  if (isNaN(dragObj.elStartTop))  dragObj.elStartTop  = 0;
		  if (isNaN(dragObj.elStartWidth)) dragObj.elStartWidth = 0;
		  	
		  // Capture mousemove and mouseup events on the page.
		
		  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;
		
		  // Get cursor position with respect to the page.
		
		  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;
		  }
		
		  // Move drag element by the same amount the cursor has moved.
		
		  if (cual==0) {
			  if ((dragObj.elStartLeft + x - dragObj.cursorStartX)>0) {
				  dragObj.elNode.style.left = (dragObj.elStartLeft + x - dragObj.cursorStartX) + "px";
			  } else {
			  	  dragObj.elNode.style.left = "0px";
			  }
			  if ((dragObj.elStartTop  + y - dragObj.cursorStartY)>0) {
			  	  dragObj.elNode.style.top  = (dragObj.elStartTop  + y - dragObj.cursorStartY) + "px";
			   } else {
			  	  dragObj.elNode.style.top = "0px";
			  }
		  }
		  if (cual==1) {
		 	dragObj.elNode.style.width = (dragObj.elStartWidth + (x - dragObj.cursorStartX)) + "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);
		  }
		  
		if (browser.isIE) {
			dragObj.elNode.style.filter = "alpha(opacity=100);"; 
		} else {
			dragObj.elNode.style.opacity = dragObj.elStartOpacity;
		}
		dragObj.elNode.style.zIndex = dragObj.elStartZIndex;
		  
		  
		}

		function cerrar(idmensaje) {
			document.getElementById('ventana' + idmensaje).style.display="none"; 
		}