​x
 
<html>
<body>
​
<img id="planets"
src="/i/eg_planets.jpg" 
usemap="#planetmap" />
​
<map name="planetmap">
<area
shape="circle"
coords="180,139,14"
href ="/example/html/venus.html"
target ="_blank"
alt="Venus" />
</map>
​
<p>单击按钮以显示图像的 usemap 属性的值。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p id="demo"></p>
​
<script>
function myFunction() {
  var x = document.getElementById("planets").useMap;
  document.getElementById("demo").innerHTML = x;
}
</script>
​
</body>
</html>
​
​
​