JavaScript中的JSON长度返回字符数，而不是数组元素数

Question

嗨，我有问题，我尝试了类似的事情并回答，但Object.keys（data）.length都没有帮助我。 这是我的JSON

{
    "POSTS": [
        [
            {
                "term_id": 1,
                "name": "Uncategorized",
                "slug": "uncategorized",
                "term_group": 0,
                "term_taxonomy_id": 1,
                "taxonomy": "category",
                "description": "",
                "parent": 0,
                "count": 1,
                "filter": "raw",
                "cat_ID": 1,
                "category_count": 1,
                "category_description": "",
                "cat_name": "Uncategorized",
                "category_nicename": "uncategorized",
                "category_parent": 0
            },
            {
                "term_id": 2,
                "name": "Nova",
                "slug": "nova",
                "term_group": 0,
                "term_taxonomy_id": 2,
                "taxonomy": "category",
                "description": "",
                "parent": 0,
                "count": 1,
                "filter": "raw",
                "cat_ID": 2,
                "category_count": 1,
                "category_description": "",
                "cat_name": "Nova",
                "category_nicename": "nova",
                "category_parent": 0
            },
            {
                "term_id": 3,
                "name": "nova1",
                "slug": "nova1",
                "term_group": 0,
                "term_taxonomy_id": 3,
                "taxonomy": "category",
                "description": "",
                "parent": 0,
                "count": 1,
                "filter": "raw",
                "cat_ID": 3,
                "category_count": 1,
                "category_description": "",
                "cat_name": "nova1",
                "category_nicename": "nova1",
                "category_parent": 0
            },
            {
                "term_id": 4,
                "name": "nova2",
                "slug": "nova2",
                "term_group": 0,
                "term_taxonomy_id": 4,
                "taxonomy": "category",
                "description": "",
                "parent": 3,
                "count": 1,
                "filter": "raw",
                "cat_ID": 4,
                "category_count": 1,
                "category_description": "",
                "cat_name": "nova2",
                "category_nicename": "nova2",
                "category_parent": 3
            },
            {
                "term_id": 5,
                "name": "nova3",
                "slug": "nova3",
                "term_group": 0,
                "term_taxonomy_id": 5,
                "taxonomy": "category",
                "description": "",
                "parent": 3,
                "count": 1,
                "filter": "raw",
                "cat_ID": 5,
                "category_count": 1,
                "category_description": "",
                "cat_name": "nova3",
                "category_nicename": "nova3",
                "category_parent": 3
            }
        ]
    ],
    "success": 1
}

这是我的JavaScript代码：

<select id ="new" name="new"></select>

<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.3.min.js"></script>

<script type="text/javascript">
   $(document).ready(function(e) {
        var select = document.getElementById("new");
        $.ajax({
             type: "POST",
             url: "wp-content/themes/twentyfourteen/ajax.php", // this script returns my JSON 
             data: ({canum: 0}), 
             success: function(data){
                 console.log(Object.keys(data).length);
             }
        });
   });
</script>

这返回我1445作为长度而不是我需要的5，如何在JSON中获取段数如何获取5而不是字符数？

你能帮我吗 ？ 谢谢。

Answer 1

您需要JSON.parse数据。 就您而言，它不是作为application/json发送的，而是作为text/html发送的。

您的成功功能应执行以下操作：

success: function(data){
    data = JSON.parse(data);
    console.log(Object.keys(data).length);
}

---

或者，如果您不想使用JSON.parse数据，而让jQuery管理它，则可以尝试此操作。 您可以在服务器中的config对象中传递期望的dataType ：

$.ajax({
    type: "POST",
    url: "wp-content/themes/twentyfourteen/ajax.php", // this script returns my JSON 
    data: ({canum: 0}),
    success: function (data) {
        console.log(Object.keys(data).length);
    },
    dataType: 'json' // <- Add this
});

这是$.ajax的文档，其中讨论了该键的选项。

---

最后一个选择是，您可以使用$ .getJson（）代替，它是上述方法的简写版本。