需求：
<html>
<head>
<title>简单的表格网页布局</title>
<meta charset="UTF-8">
</head>
<body topmargin="0">
<table width="960px" align="center" border="0" cellpadding="0" cellspacing="0">
<tr bgcolor="red" height="90" align="center"><td><font color="white" size="6"><b>网页头部</b></font></td></tr>
<tr bgcolor="green">
<td width="100%">
<table height="500" border="0" bgcolor="yellow" width="30%" align="left">
<tr><td align="center"><font color="white" size="6"><b>网页左部</b></font></td></tr>
</table>
<table height="500" border="0" bgcolor="#f60" width="70%">
<tr><td align="center"><font color="white" size="6"><b>网页右部</b></font></td></tr>
</table>
</td>
</tr>
<tr bgcolor="red" height="90" align="center"><td><font color="white" size="6"><b>网页低部</b></font></td></tr>
</table>
</body>
</html>