var banner = new Array(2); 
banner[0] = "images/banner_0b_home.jpg";
banner[1] = "images/banner_0a_home.jpg";

function pickRandom(range) { 
	if (Math.random) {
		return Math.round(Math.random() * (range-1)); 
	} else { 
		var now = new Date(); 
		return (now.getTime() / 1000) % range; 
	} 
}  

var bannerChoice = pickRandom(banner.length);