<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<style>
TD
{
        border: 4px solid;
}
</style>
<script>
function longTD()
{
        var td = document.getElementById("td2");
        td.style.height = "60px";
}

function shortTD()
{
        var td = document.getElementById("td2");
        td.style.height = "20px";
}
</script>
</head>
<body>
<form>
<input style="display:block;" type="button" onclick="longTD();" value="[Step 1] Set cell height to 60px">
<input style="display:block;" type="button" onclick="shortTD();" value="[Step 2] Set cell height to 20px">
</form>
<table>
        <tr><td id="td1">1</td><td>2</td></tr>
        <tr><td id="td2">2</td><td>2</td></tr>
</table>
</body>
</html>