var usedPics = new Array();
var max = 39;

function nextPic() {
	el = document.getElementById("main_pic");
	var pic = "pic_gal/"+get_random()+".jpg";
	el.src = pic;
	setTimeout(nextPic, 3000);
}

function get_random() {
	var ranNum = Math.floor(Math.random()*max)+1;
	while (!inArray(ranNum)) {
		ranNum = Math.floor(Math.random()*max)+1;
	}
        return ranNum;
}

function inArray(n) {
	if (usedPics.length == max) {
		usedPics = new Array();
	} else {
		for(i=0;i<usedPics.length;i++) {
			if (usedPics[i] == n)
				return false;
		}
	}
	usedPics.push(n);
	return true;
}



window.onload=nextPic;