Code
<script type="text/javascript">
sha=Math.floor(Math.random() * 2);
document.write('<img src="http://narutoplanet.net.ru/logos/logo'+sha+'.jpg" border="0" />');
</script>
Code
<script type="text/javascript">
function shapka(n)
{document.write('<img border="0" src="/logo/'+n+'.gif">');}
var h=(new Date()).getHours();
if (h > 6 && h < 21) shapka('1');
if (h > 21 || h <7) shapka('2');
</script>