что не так в этом простом коде
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script language="JavaScript" src="2.js" type="text/javascript"></script>
</head>
<body onload="io()">
<table id="day">
<tr>
<td>1</td> <td>2</td>
</tr>
<tr>
<td>3</td> <td>4</td>
</tr>
</table>
</body>
</html>
2.js
function io()
{ var ty=document.getElementById('day')
var tab=ty.getElementsByTagName('td')
for (var i=0; i=tab.length; i++) {
tab[i].Style.color='#FFFF00'
}
}