var oldNavBgElem = null;
var navBgId 	= "navBg";
var baseNavBgId	= "baseNavBg";
var navTableId 	= "navTable";

function setBaseNavBg()
{
	oldNavBgElem = document.getElementById(baseNavBgId);
	setNavBg(oldNavBgElem);
}

function setNavBg(elem)
{
	if(elem)
	{		
		showNavBg();
		
		var rrrr 			= document.getElementById(navTableId);
		var navBg 			= document.getElementById(navBgId);
		
		navBg.style.left 	= (elem.offsetLeft + rrrr.offsetLeft - 8) + "px";
		navBg.style.width 	= (elem.offsetWidth + 16) + "px";
		navBg.style.visibility = "visible";
	}
	else
	{
		hideNavBg();
	}
}

function hideNavBg() 
{
	document.getElementById(navBgId).style.visibility="hidden";
}
	
function showNavBg() 
{
	document.getElementById(navBgId).style.visibility="visible";
}


function resetNavBg()
{
	setNavBg(oldNavBgElem);
}