javascript - responseText 数组无法正确解析

Question

我正在使用 ajax 从我的 php 解析器检索 json_encode() 数组。

响应文本为["4.wav","2.wav","3.wav","6.mp3","1.mp3","5.wav"]

如果我将其放入数组中，如下所示:

var myArray = ["4.wav","2.wav","3.wav","6.mp3","1.mp3","5.wav"];

myArray 将返回

4.wav, 2.wav, 3.wav, 6.mp3, 1.mp3, 5.wav 

myArray.length 计数如预期为 6，对吧？

但是如果我将我的responseText放入var中并且像这样:

var myArray = event.target.responseText;

myArray 将返回

["4.wav","2.wav","3.wav","6.mp3","1.mp3","5.wav"]

myArray.length 计数为 49。

有人可以解释一下这里到底发生了什么吗？

这是我如何进行 ajax 调用:

    var ajax = new XMLHttpRequest();

    ajax.addEventListener("load", function(event){  
    var response = event.target.responseText;});

    ajax.open("POST", "parser.php");
    ajax.send();

提前致谢:)

Answer 1

因为 event.target.responseText 不是数组，而是字符串。字符串对象的长度是指字符串中字符的数量。您需要对响应调用 JSON.parse 以获得您想要的正确格式。

var responseText = '["4.wav","2.wav","3.wav","6.mp3","1.mp3","5.wav"]';

responseText.length //49 at this point, the length of the string

var responseArray = JSON.parse(responseText);

responseArray.length //6, because it's an array