JavaScript for/in 语句循环遍历对象的属性 - 在线编辑器

          <p>点击下面的按钮，循环遍历对象 "person" 的属性。</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
  function myFunction() {
    var x;
    var txt = "";
    var person = {
      fname: "Bill",
      lname: "Gates",
      age: 56
    };
    for (x in person) {
      txt = txt + person[x];
    }
    document.getElementById("demo").innerHTML = txt;
  }
</script>
        