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<!DOCTYPE html>
<html>
<body>
​
<h3>演示如何访问 MAP 元素</h3>
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<img src="/i/eg_planets.jpg" border="0" usemap="#myMap" alt="Planets" />
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<map name="myMap" id="myMap">
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<area
shape="circle"
coords="180,139,14"
href ="/example/html/venus.html"
target ="_blank"
alt="Venus" />
​
<area
shape="circle"
coords="129,161,10"
href ="/example/html/mercur.html"
target ="_blank"
alt="Mercury" />
​
<area
shape="rect"
coords="0,0,110,260"
href ="/example/html/sun.html"
target ="_blank"
alt="Sun" />
​
</map>
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<p>点击按钮来获得图像映射中 area 元素的数目。</p>
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<p id="demo"></p>
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<button onclick="myFunction()">试一下</button>
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<script>
function myFunction()
{
var x = document.getElementById("myMap").areas.length;
document.getElementById("demo").innerHTML = x;
}
</script>
​
</body>
</html>
​