json操作问题

1、js遍历json问题

 function e()
 {
    var json=[{"kl_id":"2","kl_title":"Test date","kl_content":"Test date","kl_type":"1","id":"1"},{"kl_id":"2","kl_title":"Test","kl_content":"Test","kl_type":"1","id":"2"}]
    var str = "";
    for (var one in json)
    {
        for(var key in json[one])
        {
            str += json[one][key] + ",";
        }
    }
    document.form.txtName.value = str;
 }