var nav_subTimer = 0;	// Subnav timer
var nav_subIn = false;	// Subnav semaphore
var nav_subNum = 7;		// Number of subnav items

// Highlight image
function nav_mainOn(id) {
	document.getElementById("nav_main" + id).src = nav_imgPath + "/images/menu" + id + "_on.gif";
}

// Turn off image highlight
function nav_mainOff(id) {
	document.getElementById("nav_main" + id).src = nav_imgPath + "/images/menu" + id + "_off.gif";
}

// Show Subnav
function nav_subShow(id) {
	clearTimeout(nav_subTimer);
	nav_subHide();
	if (id) {
		nav_mainOn(id);
		document.getElementById("nav_sub" + id).style.visibility = "visible";
	}
}

// Hide All Subnavs
function nav_subHide() {
	for (i=1; i<=nav_subNum; i++) {
		theSub = document.getElementById("nav_sub" + i);
		if (!nav_subIn && theSub) {
			nav_mainOff(i);
			theSub.style.visibility = "hidden";
		}		
	}
}

// Set Subnav On
function nav_subOn() {
	clearTimeout(nav_subTimer);
	nav_subIn = true;
}

// Set Subnav Off
function nav_subOff() {
	clearTimeout(nav_subTimer);
	nav_subIn = false;
	nav_subTimer = setTimeout("nav_subShow(nav_mainNum);",500);
}