<html>
<body>
<p>输入你的年龄并点击按钮:</p>
<input id="age" value="18">
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var age,voteable;
age = document.getElementById("age").value;
voteable = (age < 18) ? "Too young":"Old enough";
document.getElementById("demo").innerHTML = voteable + " to vote.";
}
</script>
</body>
</html>