js Json用法

 
   
   1、遍历JSON对象代码如下： 
   
   
   var packJson  = {"name":"Liza", "password":"123"} ;

for(var k in packJson ){//遍历packJson 对象的每个key/value对,k为key
   alert(k + " " + packJson[k]);
} 
   
   
   2、遍历JSON数组代码如下： 
   
   
     
   
  var packJson = [{"name":"Liza", "password":"123"}, {"name":"Mike", "password":"456"}];

for(var i in packJson){//遍历packJson 数组时，i为索引
   alert(packJson[i].name + " " + packJson[i].password);
}

  ajax(url, function (resText) {
                console.log(resText);
                var obj = JSON.parse(resText);
                for (var i in obj) {
                    console.log(obj[i].UserName);
                }
            });