<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>按钮检测年龄</title>
</head>
<body>
<p>点击按钮检测年龄</p>
年龄:<input id="age" value="18"/><p>是否达到法定投票年龄?</p>
<button onclick="mf()">点击按钮</button>
<p id="demo"></p>
<script>
function mf()
{
var age,voteable;
age=document.getElementById("age").value;
voteable=(age<18)?"年龄太小":"年龄已达到";
document.getElementById("demo").innerHTML=voteable;
}
</script>