tryjsref_iframe_longdesc 在线代码实例

 <iframe id="myframe" src="//" longdesc="w3s.txt">
<p>Your browser does not support iframes.</p>
</iframe>

<p>The URL of the long description is:
<script>
document.write(document.getElementById("myframe").longDesc);
</script>
</p><p>


</p>