返回图片的 longDesc 属性

<img id="compman" src="/examples/compman.gif" longdesc="description.htm" alt="Computerman" width="107" height="98">

<br>

<p>longdesc属性的值为:

  <script>

    var x = document.getElementById("compman");

    document.write(document.getElementById("compman").longDesc);

  </script>

</p>