修改json对象的每一个值

function fun1(obj){  
  var names={};    
    /*for in 可以用于数组或者对象*/
  for(var name in obj){    
    names[name] = obj[name].toLowerCase()
  } 
  console.log(names); 
};
var obj1 = {username: 'NAME', password: 'WOSHIDHS123'};
fun1(obj1);