function getPageScroll(){

	var yScroll;

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){	 // Explorer 6 Strict
		yScroll = document.documentElement.scrollTop;
	} else if (document.body) {// all other Explorers
		yScroll = document.body.scrollTop;
	}

	arrayPageScroll = new Array('',yScroll) 
	return arrayPageScroll;
}



function getPageSize(){
	
	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		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;
	if (self.innerHeight) {	// all except Explorer
		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;
	}

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}

	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
	
}


function popup(url) {
		
		if (url != "cerrar")
			{
				var arrayPageSize = getPageSize();
				var arrayPageScroll = getPageScroll();
				var lightboxTop = arrayPageScroll[1]  + (arrayPageSize[3] / 10)
				
				
				var objBody = document.getElementsByTagName("body").item(0);
				var objOverlay = document.createElement("div");
				objOverlay.setAttribute('id','overlay_popup');
				objOverlay.onclick = function() { popup('cerrar'); }
				objBody.appendChild(objOverlay);
				
				
				document.getElementById('overlay_popup').style.height = arrayPageSize[1]+'px';
				objOverlay.innerHTML = '<div id="popup" style="margin-top:'+lightboxTop+'px"><iframe id="popup_contenido" frameborder="0" scrolling="no"></iframe><a href="javascript:;" onclick="popup(\'cerrar\')" class="btn_cerrar" >Cerrar</a></div>';
				document.getElementById('popup_contenido').src = url;

			}
		else 
			{				
				var objOverlay = document.getElementById('overlay_popup');
				var objBody = objOverlay.parentNode;
				objBody.removeChild(objOverlay);
			}
		
		}