<script type="text/javascript">  
function shapka(n)  
{document.write('<img border="0" src="/logo/'+n+'.gif">');}  
var h=(new Date()).getHours();  
if (h > 23 || h <7) shapka('1');  
if (h > 6 && h < 12) shapka('2');  
if (h > 11 && h < 19) shapka('3');  
if (h > 18 && h < 24) shapka('4');  
</script>