菜鸟教程在线编辑器

左右布局
AI 编程工具
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>
​
<img src="planets.gif" width="145" height="126" alt="Planets" usemap="#planetmap">
<map id="planetmap" name="planetmap">
<area shape="rect" coords="0,0,82,126" alt="Sun" href="sun.htm">
<area shape="circle" coords="90,58,3" alt="Mercury" href="mercur.htm">
<area shape="circle" coords="124,58,8" alt="Venus" href="venus.htm">
</map>
<p>点击按钮获取图像地图 area 元素的数目。</p>
<p id="demo"></p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
    var x = document.getElementById("planetmap").areas.length;
    document.getElementById("demo").innerHTML = x;
}
</script>
​
</body>
</html>