// TIMING FLAGS
	var pageload = 0;

// BROWSER DETECTION
	var bn = navigator.appName;
	var ba = navigator.appVersion;
	var bu = navigator.userAgent;
	var bv = parseFloat(navigator.appVersion);
	var IE = (bn == "Microsoft Internet Explorer");
		var IE3 = (IE && bv >= 3);
	var NS = (bn == "Netscape");
		var NS3 = (NS && bv >= 3);
	var ICAB = (bu.indexOf('iCab') > 0);


// HOME PAGE LAYER FUNCTIONS
function hide_layers () {if (pageload)
 {rolloff('chronos.org');}
if (pageload) {swap_layer('chronos.org','hidden'); }}
function swap_layer(l,s) {if (pageload)

{// var s = hidden | visible
        if (ver5) {eval('document.getElementById("' + l + 'Menu").style.visibility="' + s + '"');}
        else if (ver4) {if (IE) {eval('document.all("' + l + 'Menu").style.visibility="' + s + '"');}
        else {eval('document.layers["' + l + 'Menu"].visibility="' + s + '"');}}}}


// RANDOM IMAGE
var n = 1; // default image
var r = 5; // total number of images -1
if (IE3 || NS3) {n = (Math.round(Math.random()*r) + 1);} // Math.random does not work in NS2
function random_image() 

{document.write('<a onmouseover=\'hide_layers();\' onmouseout=\'hide_layers();\' onclick="popcustom(\'\',\'custom\',235,200,420,210);" target="custom">');
document.write('<img src="http://www.chronos.org/animated1/images/' + n + '.gif" title="" alt="facets of chronostratigraphy" width=600 height=125 border=0><\/a>');}

random_image();