判断json对象是否为空并删除key

jquery方法

  var data = {};
  var b = $.isEmptyObject(data);
  alert(b);//true

将json对象转化为json字符串，再判断该字符串是否为"{}"

var data = {};
var b = (JSON.stringify(data) === "{}");
alert(b);//true

删除json对象中的key

for(var key in student){
delete student[key];
}
console.log(student);