在JavaScript中的JSON長度返回字符數，而不是數組元素數

Question

嗨我有問題，我嘗試了類似的東西，並回答，但沒有Object.keys（數據）。長度不幫助我。這裏是我的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 
} 

這裏是我的javascript代碼：

<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> 

這將返回我1445的長度不是5，因爲我需要，如何讓JSON段數如何得到5，而不是的字符數量？

你能幫助我嗎？謝謝。

Answer 1

您需要JSON.parse的數據。在你的情況下，它不是作爲application/json發送的，而是作爲text/html發送的。

您的成功，函數應該做這樣的事情：

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

---

作爲替代方案， 你雖然可以試試這個，如果你不想JSON.parse數據，只是有jQuery的管理它。您可以通過dataType你期望從服務器返回的在你的配置對象：

$.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 
}); 

這裏是談論該鍵的選項documentation for $.ajax。

---

而作爲一個最後的選擇，可以使用$.getJson()反而是上面的簡寫版本。