.head{
width:100%
height:60px
}
.main{
width:70%
height:400px
float:left
}
.main{
width:30%
height:400px
float:right
}
.footer{
width:100%
height:60px
}
</style>
<div class ="head">这里是head区域</div>
<div class ="main">这里是主要内容区域</div>
<div class="main_left">这里是右侧区域</div>
<div class="footer">这里是页脚区域</div>
function createTable(){document.write("<table border='2' width='300' height='200'><tr><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td></tr></table>")
}
<input type="button" value="生成" onclick="createTable()"/>