代码示例：（标识：dhtm_form_bg_checkbox）
<html>
<head>
<script type="text/javascript">
function bgChange(bg)
{
document.getElementById('x').style.background="url(" + bg + ")"
}
</script>
</head>
<body>
<p>本例演示如何改变单选按钮的背景颜色。</p>
<p>请把鼠标移动到下面的三个表格单元上，背景颜色将会改变：</p>
<table width="300" height="100">
<tr>
<td onmouseover="bgChange('/static/demo/images/eg_bg_03.gif')"
background="/static/demo/images/eg_bg_03.gif">
</td>
<td onmouseover="bgChange('/static/demo/images/eg_bg_04.gif')"
background="/static/demo/images/eg_bg_04.gif">
</td>
</tr>
</table>
<form>
请把鼠标移动到图像上：
<input id="x" type="checkbox" checked value="ON">
</form>
</body>
</html>
