查看一個簡單的jQuery的例子來遍歷一個JavaScript數組對象。
- var?json?=?[??
- {"id":"1","tagName":"apple"},??
- {"id":"2","tagName":"orange"},??
- {"id":"3","tagName":"banana"},??
- {"id":"4","tagName":"watermelon"},??
- {"id":"5","tagName":"pineapple"}??
- ];??
- ??
- $.each(json,?function(idx,?obj)?{??
- alert(obj.tagName);??
- });??
上面的代碼片斷工作正常,提示 “apple”, “orange” … 等,如預期一樣。
問題: JSON 字符串
下面的例子中,聲明了一個JSON字符串(隨附單或雙引號)直接地。
- var?json?=?'[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},??
- {"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},??
- {"id":"5","tagName":"pineapple"}]';??
- ??
- $.each(json,?function(idx,?obj)?{??
- alert(obj.tagName);??
- });??
在Chrome中,它顯示在控制臺下面的錯誤:
Uncaught TypeError: Cannot use 'in' operator to search for '156'?
in [{"id":"1","tagName":"apple"}...
解決方案:JSON字符串轉換為JavaScript對象。
要修復它,通過標準JSON.parse()或jQuery 的 $.parseJSON 將其轉換為JavaScript對象。
- var?json?=?'[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},??
- {"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},??
- {"id":"5","tagName":"pineapple"}]';??
- ??
- $.each(JSON.parse(json),?function(idx,?obj)?{??
- alert(obj.tagName);??
- });??
- ??
- //or???
- ??
- $.each($.parseJSON(json),?function(idx,?obj)?{??
- alert(obj.tagName);??
- }); ?