/***********************************************
* Drop Down/ Overlapping Content- © Dynamic Drive (www.dynamicdrive.com)
* This notice must stay intact for legal use.
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/

function getposOffset(overlay, offsettype){
var totaloffset=(offsettype=="left")? overlay.offsetLeft : overlay.offsetTop;
var parentEl=overlay.offsetParent;
while (parentEl!=null){
totaloffset=(offsettype=="left")? totaloffset+parentEl.offsetLeft : totaloffset+parentEl.offsetTop;
parentEl=parentEl.offsetParent;
}
return totaloffset;
}

function overlay(curobj, subobjstr, cambio_color, opt_position){ // cambio_color= id del tag a cambiar su background
	if (document.getElementById){
		var subobj=document.getElementById(subobjstr);
		subobj.style.display=(subobj.style.display!="block")? "block" : "none"
		var xpos=getposOffset(curobj, "left")+((typeof opt_position!="undefined" && opt_position.indexOf("right")!=-1)? -(subobj.offsetWidth-curobj.offsetWidth) : 0) 
		var ypos=getposOffset(curobj, "top")+((typeof opt_position!="undefined" && opt_position.indexOf("bottom")!=-1)? curobj.offsetHeight : 0)
		subobj.style.left=xpos+"px";
		subobj.style.top=ypos+"px";
		
		/* CAMBIO DE COLOR DE CAPA*/
		var cambio_texto=document.getElementById(cambio_color); // se obtiene el elemento por su id
		cambio_texto.className=(cambio_texto.className!="plegado")? "plegado" : "desplegado"; //se cambia el fondo de la etiqueta de la clase .plegado a la clase .desplegado
		return false
	}
	else return true
}

function overlayclose(subobj){
document.getElementById(subobj).style.display="none"
}