<input type=button onclick="document.all.mxh.style.visibility='hidden'" value=hidden>
<input type=button onclick="document.all.mxh.style.visibility='visible'" value=visible>
<iframe id=mxh src="http://colorweb.go.163.com"></iframe>
<input type=button onclick="document.all.mxh.style.visibility='visible'" value=visible>
<iframe id=mxh src="http://colorweb.go.163.com"></iframe>
<input type="button" value="change size" onclick="frm.resizeTo(400,400);">
<input type="button" value="show" onclick="document.all('frm').style.visibility = 'visible';">
<input type="button" value="hide" onclick="document.all('frm').style.visibility = 'hidden';">