指定した時間で背景色が入れ替わる？
<script type="text/javascript">
<!--
myBack= new Array();
myBack[0]="#ffffcc";
myBack[1]="#ccffff";
myBack[2]="#ffccff";
myBack[3]="#ccccff";
myBack[4]="#cccccc";
myBack[5]="#ccffcc";
myBack[6]="#ffcccc";
my_time=1; n=0; cnt=0;
function my_bgcolor()
{
document.bgColor=myBack[cnt];
cnt++;
if(cnt>=myBack.length)cnt=0;
clearTimeout(n);
n=setTimeout('my_bgcolor();',my_time*3000);
}
//-->
</script>
</head>
<body onLoad="my_bgcolor();">