<img src="/upload2/statics/images/course/planets.gif" width="145" height="126" usemap="#planetmap"> <map name="planetmap"> <area id="venus" shape="circle" coords="124,58,8" alt="The planet Venus" href="venus.htm"> </map> <p>金星的替代文本: <script> document.write(document.getElementById("venus").alt); </script> </p>