// function to swap images
function changeImages() {
	if (document.images) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			var argArray = arguments[i].split('.');
			var objName;
			if ((document.layers && argArray.length > 1) || argArray.length <= 1) {
				objName = eval("document." + arguments[i]);
			} else {
				objName = eval("document." + argArray[argArray.length - 1]);
			}
			objName.src = eval(changeImages.arguments[i+1] + ".src");
		}
	}
}

// function to roll a nav button on
function navOn(which) {
	changeImages("nav_"+which,"nav_"+which+"_on");
	return true;
}
// function to roll a nav button off
function navOff(which) {
	changeImages("nav_"+which,"nav_"+which+"_off");
	return true;
}

// dhtml layer variables for cross-browser compatability
if (document.layers) {	// Netscape 4
	doc = "document[";
	conDoc = "document";
	docClose = "]";
	sty = "";
	htm = ".document";
} else if (document.getElementById) {	// NS 6 or IE 5 and up (W3C compliant browsers).
	doc = "document.getElementById(";
	conDoc = "document.getElementById(";
	docClose = ")";
	sty = ".style";
	htm = ".document";
} else if (document.all) {	// IE 4
	doc = "document.all[";
	conDoc = "document.all[";
	docClose = "]";
	sty = ".style";
	htm = "";
}