var tabs_toggled = new Array();

var NS4 = (document.layers) ? 1 : 0;	// check for Netscape 4
var IE4 = (document.all) ? 1 : 0;	// check for IE 4
var NS6 = ((document.getElementById) && (!document.all)) ? 1 : 0; // check for Netscape 6 (or Mozilla)

function gotoURL(url) {
	location = url;
}

function preloadTabImage(img) {
	var img = new Image();
	img.src = img;
}

preloadTabImage('images/tab_left_g_dn.gif');
preloadTabImage('images/tab_right_g_dn.gif');

function toggleTab(id) {
	for (var i=0; i<tabs_toggled.length; i++) {
		if (tabs_toggled[i] == id) {
			// already toggled, turn it off
			tabToggleOff(id);
			tabs_toggled.splice(i,1); // remove from the array
			return;
		}
	}

	tabToggleOn(id);
	tabs_toggled.push(id); // add to the array
}

function tabToggleOn(id) {
	tabDown(id);

	if (id == 'tut') {
	}
}

function tabToggleOff(id) {
	tabUp(id);

	if (id == 'tut') {
	}
}

function tabDown(id) {
	var idh3 = id + "_h3";

	if (NS4) {
		var tabdiv = document[id];
		var tabh3 = document[idh3];
	} else if (IE4) {
		var tabdiv = document.all[id].style;
		var tabh3 = document.all[idh3].style;
	} else {
		var tabdiv = document.getElementById(id).style;
		var tabh3 = document.getElementById(idh3).style;
	}

	if (tabdiv && tabh3) {
		tabdiv.backgroundImage = 'url(graphics/tab_right_g_dn.gif)';
		tabh3.backgroundImage = 'url(graphics/tab_left_g_dn.gif)';
	}
}
function tabUp(id) {
	var idh3 = id + "_h3";

	if (NS4) {
		var tabdiv = document[id];
		var tabh3 = document[idh3];
	} else if (IE4) {
		var tabdiv = document.all[id].style;
		var tabh3 = document.all[idh3].style;
	} else {
		var tabdiv = document.getElementById(id).style;
		var tabh3 = document.getElementById(idh3).style;
	}

	if (tabdiv && tabh3) {
		tabdiv.backgroundImage = 'url(graphics/tab_right_g.gif)';
		tabh3.backgroundImage = 'url(graphics/tab_left_g.gif)';
	}
}