theObjects = new Array();
theObjects[0] = '<iframe width="733" height="80" frameborder="0" style="background-color:#000000;border:1px solid black;" src="banners/giyoza.swf"></iframe>'; 
theObjects[1] = '<iframe width="733" height="80" frameborder="0" style="background-color:#000000;border:1px solid black;" src="banners/giyoza.swf"></iframe>'; 


document.write(theObjects[get_random()]);
function get_random()
{
    var ranNum= Math.floor(Math.random()*2);
    return ranNum;
}