JSON的parse()方法介绍

JSON.parse(text[, reviver])

<p id="demo"></p>
<script>
var obj = JSON.parse('{ "name":jb51", "alexa":10000, "site": }');
document.getElementById("demo").innerHTML = obj.name + "" + obj.site;
</script>

eg:
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
myObj = JSON.parse(this.responseText);
document.getElementById("demo").innerHTML = myObj.name;
} };
xmlhttp.open("GET", "/try/ajax/json_demo.txt", true); xmlhttp.send();

<p id="demo"></p>
<script>      //将字符串转换为data对象
var text = '{ "name":"csdn", "initDate":"2018-12-14", "site":}';
var obj = JSON.parse(text);
obj.initDate = new Date(obj.initDate);
document.getElementById("demo").innerHTML = obj.name + "创建日期: " + obj.initDate;
</script>

<p id="demo"></p>
<script>
var text = '{ "name":"csdn", "initDate":"2018-12-14", "site":".jb51."}';
var obj = JSON.parse(text, function (key, value) {
  if (key == "initDate") {
    return new Date(value);
  } else {
    return value;
}});
document.getElementById("demo").innerHTML = obj.name + "创建日期" + obj.initDate;

var text = '{ "name":"jb51", "alexa":"function () {
return 10000;}",
"site":".jb51."}';
var obj = JSON.parse(text);
obj.alexa = eval("(" + obj.alexa + ")");      注意最好不要在json中使用函数
document.getElementById("demo").innerHTML = obj.name + " Alexa 排名" + obj.alexa();