{"id":"1","tagName":"apple"},

{"id":"2","tagName":"banana"},

{"id":"3","tagName":"orange"},

{"id":"4","tagName":"watermelon"},

{"id":"5","tagName":"pineapple"}];

$.each(json,function(idx,obj)

{alert(obj.tagName);

但是如果声明的是一个json字符串（用单引号或双引号），那么不能直接用上面的方法遍历，否则会报错：

var json='[

{"id":"1","tagName":"apple"},

{"id":"2","tagName":"banana"},

{"id":"3","tagName":"orange"},

{"id":"4","tagName":"watermelon"},

{"id":"5","tagName":"pineapple"}]';

$.each(json,function(idx,obj){alert(obj.tagNmae);});

所以如果声明的是字符串，那么便遍历的时候应该先用json.parse()或者jquery的方法$.parseJSON将字符串转化为JavaScript对象

$.each(JSON.parse(json),function(idx,obj)

{alert(obj.tagNmae);

$.each(JSON.parse(json),function(idx,obj)

{alert(obj.tagNmae);