解决iframe在页面中无法自适应

<script type="text/javascript" language="javascript">// <![CDATA[
function resizeHeight()
{
document.getElementById("web".style.height = parseInt(document.body.clientHeight-50);
}
// ]]></script>
<iframe id="web" name="web" src="about:blank" frameborder="0" scrolling="NO" width="100%" height="240"></iframe>