实例 » - 在线编辑器

          <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) ? "太年轻而不能" : "年龄够";
    document.getElementById("demo").innerHTML = voteable + "投票";
  }
</script>
        