<script type="text/javascript">
<!--
document.getElementById("tdStyle").style.backgroundColor='red';
//-->
</script>
<script type="text/javascript">
<!--
document.getElementById("tdStyle").style.backgroundColor='red';
//-->
</script>
<script type="text/javascript">
<!--
document.getElementById("tdStyle").style.backgroundColor='red';
//-->
</script>
<head>
<script language="javascript">
function changeColor(){
//var x=document.getElementById("tdStyle").class ="tds"
document.getElementById("tdStyle").style.backgroundColor='red';//alert(x)
}
</script>
<title>无标题文档</title>
</head>
<style type="text/css">
.tds{ background-color:#000000}
</style>
<body>
<form id="form1" name="form1" method="post" action="">
<table width="80%" border="1" cellspacing="1" cellpadding="1">
<tr >
<td id="tdStyle" ><label>
<input type="submit" name="Submit" value="提交" onClick="changeColor()" />
<span >dsfsdfdf</span></label></td>
<td align="center" > </td>
</tr>
</table>
</form>
</body>
</html>
请问通过按钮怎么改变不了单元格背景色