var idx = 0;
var ifirst = 1;

var link = new Array(
	"http://www.concept-tours.com",
	"http://www.culturaltourconsultants.com",
	"http://chorusamerica.org/Masterclass10/index10.cfm",
	"http://www.fas.harvard.edu/~holchoir/",
	"http://www.mcclosky.org",
	"http://www.catholicyouthchoir.org"
);

var pic = new Array(
	"ads/Concept_Tours.jpg",
	"ads/Cultural_Tour.jpg",
	"ads/Chorus_America.jpg",
	"ads/Harvard_Holden_Chorus.jpg",
	"ads/McClosky_Institute.jpg",
	"ads/National_Catholic_Youth_Choir.jpg"
);

var text = new Array(
	"Concept Tours",
	"Cultural Tour",
	"Chorus America",
	"Harvard Holden Chorus",
	"McClosky Institute",
	"National Catholic Youth Choir"
);

function preload_images() {
	var preLoad = new Array();
	for (i = 0; i < pic.length; i++){
		preLoad[i] = new Image(134,230);
		preLoad[i].src = pic[i];
	}
}

function rotate() {
	if (ifirst == 1){
		idx=Math.floor(Math.random()*pic.length)
	}
	var idxlink = link[idx];
	var idxpic = pic[idx];
	var idxtext  = text[idx];
	var	pixwid = 134;
	var	pixht = 230;
	var content = '<a href=\"'+idxlink+'\"><image src=\"'+idxpic+'\" alt=\"'+idxtext+'\" width=\"'+pixwid+'\" height=\"'+pixht+'\"></a>';
	document.getElementById('ad').innerHTML = content;
	idx++;
	if(idx > pic.length-1){idx=0;}
	ifirst++;
	setTimeout("rotate()", 5000);
}