<script type="text/javascript">
function bgChange(bg)
document.body.style.background=bg
}
</script>
</head>
<body>
<b>请把鼠标移动到正方形上，背景颜色会发生改变！</b>
<table width="300" height="100">
<tr>
<td onmouseover="bgChange('red')"
onmouseout="bgChange('transparent')"
bgcolor="red">
</td>
<td onmouseover="bgChange('black')"
onmouseout="bgChange('transparent')"
bgcolor="black">
</td>
<td onmouseover="bgChange('green')"
onmouseout="bgChange('transparent')"
bgcolor="green">
</td>
</tr>
</table>