/*
  * Display a popup
  */
function openPopup(){
	var overlay = document.getElementById("overlay");
	var popup	= document.getElementById("popup_div");
	
	overlay.style.display 	= "inline";
	popup.style.display 	= "inline";
	
	document.documentElement.style.overflow = "hidden";
}
/*
  * Close a popup
  */
function closePopup(){
	var overlay = document.getElementById("overlay");
	var popup	= document.getElementById("popup_div");
	var url 	= document.location;
	
	overlay.style.display 	= "none";
	popup.style.display 	= "none";
	
	document.documentElement.style.overflow = "auto";
}