Moin!
Du brauchst keine ID:
<html>
<head>
<title></title>
<script type="text/javascript">
function Einfaerben (table,farbe) {
table.style.backgroundColor = farbe;
}
</script>
</head>
<body>
<table id=1 onMouseover="javascript:Einfaerben (this,'red');">
<tr>
<td>fdgsdfgsdfg</td>
</tr>
</table>
<table id=2 onMouseover="javascript:Einfaerben (this,'yellow');">
<tr>
<td>sdfgsdfgsdg</td>
</tr>
</table>
</body>
</html>
-- Skeeve