你可以使用索引值来修改数组

<p>修改 JSON 对象数组值。</p>

​

<p id="demo"></p>

​

<script>

  var myObj, i, x = "";

  myObj = {

    "name": "网站",

    "num": 3,

    "sites": ["Google", "Mifengjc", "Taobao"]

  };

  myObj.sites[1] = "Github";

  for (i in myObj.sites) {

    x += myObj.sites[i] + "<br>";

  }

  document.getElementById("demo").innerHTML = x;

</script>