js解决如何在iframe框架加个打开和关闭的按钮（转载）

有人在群里问如何在iframe框架加个打开和关闭的按钮，当单击“打开”按钮就让iframe显示出来，当单击“关闭”按钮就隐藏iframe,这个功能群中给出了解决方法

具体实现操作如下：
<script language="JavaScript">
var act;
function over(){
var h = parseInt(mytd.height);
if (h <= 400){
mytd.height = h + 20;
clearTimeout(act);
act = setTimeout('over()', 10);
}
}
function out(){
var h = parseInt(mytd.height);
if (h >= 0){
mytd.height = h - 20;
clearTimeout(act);
act = setTimeout('out()', 10);
}
}
</script>
<input name="Submit" type="button" id="Submit" onClick="over()" value="打开">
<input name="Submit2" type="button" id="label" onClick="out()" value="关闭">
<table width="316" height="1" cellpadding="0" cellspacing="0" id="mytd" >
<tr>
<td ><iframe width="760" height="100%" src="" FRAMEBORDER=0 scrolling="no"></iframe></td>
</tr>
</table>