/*
 *	nav.js
 *	prepares rollovers for the LHS navigation bar
 *	using all images whose name starts with imgBase
 *	the _init function is called at load time by the main page
 */
var bgCol_rov	= "#3399cc";
var bgCol_rout	= "#006699";
 
function nav_init()
{
	if (document.images)
	{
		var imgBase	= new String("nav_");
		var iL	= imgBase.length;
		var imgL	= document.images.length;
		var src,i_src;
		//looks for 1 image in this group
		for (var i=0;i<imgL; i++)
		{
			if (document.images[i].name.substring(0,iL) == imgBase)
			{
				src	= new String(document.images[i].src);
				break;
			}
		}
		imgSwap	= doImgSwap;
	}
	
	if (document.all)
	{
		trBg	= doTrBg;
	}
	
	//uses the url of that image to work out src of rollover/rollout states
	if (src)
	{
		var i_src	= src.lastIndexOf(src_nav_rout);
		src	= src.substring(0,i_src);
		src_nav_rov		= src+src_nav_rov;
		src_nav_rout	= src+src_nav_rout;
		src_selnav_rov		= src+src_nav_rov;
	
		nav_rollover	= function(which)	{imgSwap(which,src_nav_rov);trBg(which,bgCol_rov)}
		nav_rollout		= function(which)	{imgSwap(which,src_nav_rout);trBg(which,bgCol_rout)}
		selnav_rollover		= function(which)	{/*imgSwap(which,src_selnav_rov);trBg(which,bgCol_rov)*/}
	}
	nav_init	= function(){}

}
var nav_rollover	= function(){}
var nav_rollout	= function(){}
var selnav_rollover	= function(){}
var trBg	= function(){}
function doTrBg(tr,bg)
{
	if (typeof document.all['strip_'+tr] != "undefined")	document.all['strip_'+tr].style.backgroundColor	= bg;
}
var imgSwap	= function(){}
function doImgSwap(img,src)
{
	if (typeof document.images["nav_"+img] != "undefined")	document.images["nav_"+img].src	= src;
}