function showPop() {
			document.getElementById('popVentana').style.display="";
			var h = getPageSize()[1];
			
			var combos = document.getElementsByTagName("select");
			for(var i=0;i<combos.length;i++){
			       combos[i].style.display = "none";
			}
		}
		
		
		function hidePop(){
			document.getElementById('popVentana').style.display="none";
			
			var combos = document.getElementsByTagName("select");
			for(var i=0;i<combos.length;i++){
			       combos[i].style.display = "";
			}
		}
		
		function getPageSize(){
		
			var xScroll, yScroll;
		
			if (window.innerHeight && window.scrollMaxY) {	
				xScroll = window.innerWidth + window.scrollMaxX;
				yScroll = window.innerHeight + window.scrollMaxY;
			} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
				xScroll = document.body.scrollWidth;
				yScroll = document.body.scrollHeight;
			} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
				xScroll = document.body.offsetWidth;
				yScroll = document.body.offsetHeight;
			}
		
			var windowWidth, windowHeight;
			
			//	console.log(self.innerWidth);
			//	console.log(document.documentElement.clientWidth);
		
			if (self.innerHeight) {	// all except Explorer
				if(document.documentElement.clientWidth){
					windowWidth = document.documentElement.clientWidth; 
				} else {
					windowWidth = self.innerWidth;
				}
				windowHeight = self.innerHeight;
			} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
				windowWidth = document.documentElement.clientWidth;
				windowHeight = document.documentElement.clientHeight;
			} else if (document.body) { // other Explorers
				windowWidth = document.body.clientWidth;
				windowHeight = document.body.clientHeight;
			}	
			
			// for small pages with total height less then height of the viewport
			if(yScroll < windowHeight){
				pageHeight = windowHeight;
			} else { 
				pageHeight = yScroll;
			}
		
			//	console.log("xScroll " + xScroll)
			//	console.log("windowWidth " + windowWidth)
		
			// for small pages with total width less then width of the viewport
			if(xScroll < windowWidth){	
				pageWidth = xScroll;		
			} else {
				pageWidth = windowWidth;
			}
			//	console.log("pageWidth " + pageWidth)
		
			arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
			return arrayPageSize;
			}