<html>
<head>
<script>
function cell()
{
var x=document.getElementById('myTable').rows[0].cells;
alert(x[0].innerHTML);
}
</script>
</head>
<body>
<table id="myTable" border="1">
<tr>
<td>cell 1</td>
<td>cell 2</td>
</tr>
<tr>
<td>cell 3</td>
<td>cell 4</td>
</tr>
</table>
<br>
<input type="button" onclick="cell()" value="Alert first cell">
</body>
</html>