JavaScript实现复选框选中时文字背景变色

<html>
<head>
<title>选中复选框文字变色</title>
<style>
.checkbox {
 background-Color:e-xpression(this.checked?'yellow':'buttonface');
}
</style>
</head>
<script>
function chaCloor(field){
var pig = field.checked;
pig?field.nextSibling.style.backgroundColor="skyblue":field.nextSibling.style.backgroundColor="white";
}
</script>
<body>
<table height=48 width=136>
<tr>
 <td><input type="checkbox" onClick="chaCloor(this)"><span>网页特效</span></td>
</tr>
<tr>
<td><input type="checkbox" onClick="chaCloor(this)"><span>源码下载</span></td>
</tr>
<tr>
<td><input type="checkbox" onClick="chaCloor(this)"><span>编程软件</span></td>
</tr>
</table>
</body>
</html>