返回文档的第一个链接 - 在线编辑器

          <img src="/examples/planets.gif" width="145" height="126" alt="Planets" usemap="#planetmap">
<map name="planetmap">
<area id="sun" shape="rect" coords="0,0,82,126" href="/examples/sun.htm" alt="Sun">
<area id="mercury" shape="circle" coords="90,58,3" href="/examples/mercur.htm" alt="Mercury">
<area id="venus" shape="circle" coords="124,58,8" href="venus.htm" alt="Venus">
</map>
<p><a id="javascript" href="/js/">JavaScript 教程</a></p>
<p>第一个链接/地址的ID：
  <script>
    document.write(document.links[0].id);
  </script>
</p>
        