// JavaScript Document
<!--
// 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 IE4 = (IE && bv >= 4);
		var IE41 = (IE && bv >= 4 && ba.indexOf('MSIE 4.0;') < 0 && ba.indexOf('MSIE 4.01;') < 0);
		var IE5 = (IE && bv >= 4 && ba.indexOf('MSIE 5') > 0);
	var NS = (bn == "Netscape");
		var NS3 = (NS && bv >= 3);
		var NS4 = (NS && bv >= 4);
		var NS41 = (NS && bv >= 4.1);
		var NS5 = (NS && bv >= 5);
		var NS6 = (NS5 && bv >= 4 && bu.indexOf('Netscape6') > 0);
	var ICAB = (bu.indexOf('iCab') > 0);
	var Gecko = (bu.indexOf('Gecko') > 0);
	var Safari = (bu.indexOf('Safari') > 0);
	var Mozilla = (NS5 && (bu.indexOf('ozilla') > 0) && !Safari && !NS6);

// BROWSER FLAGS
	var check_mathrandom = (IE3 || NS3 || Gecko) ? 1 : 0;

	var n = 5; // default image
	var r = 4; // total number of images -1

	if (check_mathrandom) {n = (Math.round(Math.random()*r) + 1);} // Math.random does not work in NS2

	function imagen_aleatoria()
		{
			document.write('<td width="601" height="138" background="img/top/' + n +'.gif" bgcolor="#336699">');
		}
//-->