var version = "x";
var browserName = navigator.appName;
var browserVer = parseInt(navigator.appVersion);
if (browserName == "Netscape" && browserVer >= 3) version = "ok";
else if (browserName == "Microsoft Internet Explorer" && browserVer >= 3) version = "ok";

if (version == "ok") {
             SOM0on = new Image(); SOM0on.src = "buttons/OPT01on.gif";
             SOM0off = new Image(); SOM0off.src = "buttons/OPT01.gif";
             SOM1on = new Image(); SOM1on.src = "buttons/OPT10on.gif";
             SOM1off = new Image(); SOM1off.src = "buttons/OPT10.gif";
             SOM2on = new Image(); SOM2on.src = "buttons/OPT03on.gif";
             SOM2off = new Image(); SOM2off.src = "buttons/OPT03.gif";
             SOM6on = new Image(); SOM6on.src = "buttons/OPT07on.gif";
             SOM6off = new Image(); SOM6off.src = "buttons/OPT07.gif";
             SOM7on = new Image(); SOM7on.src = "buttons/OPT08on.gif";
             SOM7off = new Image(); SOM7off.src = "buttons/OPT08.gif";
             SOM3on = new Image(); SOM3on.src = "buttons/OPT04on.gif";
             SOM3off = new Image(); SOM3off.src = "buttons/OPT04.gif";
             SOM4on = new Image(); SOM4on.src = "buttons/OPT05on.gif";
             SOM4off = new Image(); SOM4off.src = "buttons/OPT05.gif";
             SOM13on = new Image(); SOM13on.src = "buttons/OPT14on.gif";
             SOM13off = new Image(); SOM13off.src = "buttons/OPT14.gif";
             SOM14on = new Image(); SOM14on.src = "buttons/OPT15on.gif";
             SOM14off = new Image(); SOM14off.src = "buttons/OPT15.gif";
             SOM15on = new Image(); SOM15on.src = "buttons/OPT16on.gif";
             SOM15off = new Image(); SOM15off.src = "buttons/OPT16.gif";
             SOM16on = new Image(); SOM16on.src = "buttons/OPT17on.gif";
             SOM16off = new Image(); SOM16off.src = "buttons/OPT17.gif";
             SOM17on = new Image(); SOM17on.src = "buttons/OPTrising_on.gif";
             SOM17off = new Image(); SOM17off.src = "buttons/OPTrising.gif";
             SCIon = new Image(); SCIon.src = "buttons/OPTsci2on.gif";
             SCIoff = new Image(); SCIoff.src = "buttons/OPTsci2.gif";
			CNM2on = new Image(); CNM2on.src = "buttons/OPTsom_on.gif";
			CNM2off = new Image(); CNM2off.src = "buttons/OPTsom.gif";
			CNM3on = new Image(); CNM3on.src = "buttons/OPTcomp_on.gif";
			CNM3off = new Image(); CNM3off.src = "buttons/OPTcomp.gif";
 			CNM8on = new Image(); CNM8on.src = "buttons/OPTmap_on.gif";
			CNM8off = new Image(); CNM8off.src = "buttons/OPTmap.gif";
 			CNM9on = new Image(); CNM9on.src = "buttons/OPTquestions_on.gif";
			CNM9off = new Image(); CNM9off.src = "buttons/OPTquestions.gif";
             }

function img_act (imgName) {
		if (version == "ok") {
		imgOn = eval(imgName + "on.src");
		document [imgName].src = imgOn;
		}
	}
function img_inact (imgName) {
		if (version == "ok") {
		imgOff = eval(imgName + "off.src");
		document [imgName].src = imgOff; 
		}
	}

function getYear() {
	var wd = 0
	var today = new Date()
	var thisYear = today.getYear() 
	if (thisYear <=1900) thisYear += 1900
	return(thisYear)	
	}

function writeUpdate() {
	var m = document.lastModified;
	var yr = m.indexOf("20");
	var q = m.indexOf(":");
	var gmt = m.indexOf("GMT")
	var p = m.length;
	if ( yr < 7 ) return ( m.substring(0,yr+5) + ' * ' )
	else if ( gmt < 1) return ( m.substring(0,q-3) + ', ' + m.substring(yr,yr+7) + ' ** ' )
	else if ( gmt > 1) return ( m.substring(0,q-3) + ' *** ' )
	}