function roll(img_name, img_src) {
	// basic image swapping for rollovers
	if (document.images)
	{
		document[img_name].src = img_src;
	}
}

function centerPopup(pageURL, winName, w, h, scrollYesNo) {
    // new window utility
    var winl = (screen.width - w) / 2;
    var wint = (screen.height - h) / 2;
    var winprops = 'height='+h+',width='+w+',top='+wint+',left='+winl+',scrollbars='+scrollYesNo+',resizable';
    win = window.open(pageURL, winName, winprops);
    win.focus();
}

function randomString(len)
{
	var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
	var string_length = len;
	var randomstring = '';
	for (var i=0; i<string_length; i++) {
		var rnum = Math.floor(Math.random() * chars.length);
		randomstring += chars.substring(rnum,rnum+1);
	}
	return(randomstring);
}