函数prototype

声明一个对象，把方法写在原型上

var CheckObject = function(){};
CheckObject.prototype = function(){
  checkName : function(){
   return this;
  },
  checkEmail : function(){
  return this;
  }
}
var a = new CheckObject();
a.checkName().checkEmail();

抽象统一的添加方法

Function.prototype.addMethod = function(name,fn){
  this[name] =fn;
}
var methods = new Function();
methods.addMethod("checkName",function(){
    console.log("chengchao")
});
methods.chekcName();