var yPos = 0;

	function mostrarCapa() {
		
		getScroll();
		if (comprobar('msie 6')){
			
			prepararIE("100%", "visible");
			document.getElementById('desactivar').style["height"] = screen.availHeight;
			document.getElementById('desactivar').style["width"] = screen.availWidth-25;
			setScroll(0, 0);
			hideSelects("hidden");
  		}
  		visibilidadCapas("block");
	}

	function ocultarCapa() {
		
		setScroll(0, yPos);
  		if (comprobar('msie 6')){
  			prepararIE("auto", "auto");
			hideSelects("visible");
  		}
  		visibilidadCapas("none");

	}
	
	function visibilidadCapas(opcion){
  		document.getElementById('desactivar').style["display"] = opcion;
  		document.getElementById('caja').style["display"] = opcion;
	}
	function getScroll(){
		if (self.pageYOffset) {
			yPos = self.pageYOffset;
		} else if (document.documentElement && document.documentElement.scrollTop){
			yPos = document.documentElement.scrollTop; 
		} else if (document.body) {
			yPos = document.body.scrollTop;
		}
	}
	
	function setScroll(x, y){
		window.scrollTo(x, y); 
	}