​x
 
<!DOCTYPE html>
<html>
<body>
​
<p>输入您的年龄并点击按钮：</p>
​
<input id="age" value="18">
​
<button onclick="myFunction()">试一试</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>
​