var millisec = 250;
var timeoutId;
var visiblePopup = null;


/*
 * showHidePopup()
 * parameter
 * 		popupdivId - targeted popup div id
 */
function showHidePopup(popdivId)
{
	if(document.getElementById)
	{
		var obj = document.getElementById(popdivId);
		if(obj.style.visibility == "hidden" || obj.style.visibility == "")
		{
			obj.style.visibility = "visible";
    		hidepopup();
			visiblePopup=popdivId;
		}
		else
			hidepopup();
	}
	return false;
}

/*
 * delayhide() 
 * 		delays popup closing timing.
 */
function delayHide()
{
	clearPopup();
	timeoutId = setTimeout(function(){hidepopup()}, millisec);
}

/*
 * hidepopup() 
 * 		close the targetd popup when a user click the "x".
 */
function hidepopup()
{
	clearPopup();
	if(visiblePopup!=null)
	{
		var o = document.getElementById(visiblePopup);		
		visiblePopup=null;
		o.style.visibility = "hidden";
	}
	return false;
}

/*
 * clearPopup() 
 * 		cancel the setTimeout(), so when a user mouseover the popup,
 * it will not disappeared. 
 */
function clearPopup()
{
	if(typeof timeoutId != "undefined")
	{
		clearTimeout(timeoutId);
	}
}