Random_baner

<script type="text/javascript">
function banner () {

    var num = new Array();
    num[0] = "";
    num[1] = "";
    num[3] = "";

var baner = Math.floor(Math.random()*num.length)
if(baner==0){
    var baner = 1;
    document.write('<img src="'+num[baner]+'">');
}
}

banner();
</script>
<script type="text/javascript" src="script.js"></script>