var Person = function(name){
                this.name = name;
            }
            Person.prototype = {
                say: function(){
                    alert(this.name)
                },
                delay: function(t){
                    t = t || 0;
                }
            }
            
            var c = new Person(123);
            c.say().delay(1000)

 var Person = function(name){
    this.name = name;
}
Person.prototype = {
    say: function(){
        alert(this.name)
        return this
    },
    delay: function(t){
        t = t || 0;
        alert(t)
    }
}

var c = new Person(123);
c.say().delay(1000)

------解决方案--------------------
JScript code

var objPerson = function(name){
    this.name = name;    
}

objPerson.prototype = {
    say: function(){   //立即say
        alert(this.name);      
    },
    say:function(delayTime){  //延时delayTime秒say， //如不重载就改名称 delaySay即可
        var t = delayTime||0;
        var _this=this;
        setTimeout(function(){alert(_this.name);},t*1000);
    },
    /*
    delay: function(t){
        t = t || 0;
    }
    */
}

var c = new objPerson('shenzhenNBA');
c.say();  //立即say
c.say(3);  //延时3秒say

------解决方案--------------------
7楼的代码已经可以了，如果楼主一定要保留一个delay函数的话可以这样写：
           var Person = function(name){
               this.name = name;
           }
           Person.prototype = {
               say: function(){
                   alert(this.name)
               },
               delay: function(time,callBack){///callBack为延时时间到时会回调函数
                   setTimeOut(function(){callBack();},time) ;               }
           }
          
           var c = new Person(123);
           c.delay(1000,c.say)///这样将在1000毫秒后执行c.say，也可以传递其他函数来延迟执行






------解决方案--------------------
var Person = function(name){
   this.name = name;
}
Person.prototype = {
   delay: function(t){
     this.t = t || 0;
     return this;
	},
   say: function(){
		var that = this;
		window.setTimeout(function(){
			window.setTimeout(function(){
				alert(that.name)
			},that.t)
		},0);
		
		return this;
   }
};

var c = new Person(123);
c.say().delay(1000);
c.delay(1000);.say();
都可以
别的方法没有想到。。。

------解决方案--------------------
JScript code

    var Person = function (name) {
        this.name = name;
    }
    Person.prototype = {
        delay: function (t) {
            t = t || 0;
            if (this.h) {
                clearTimeout(this.h);
                this.h = null;
                this.say(this.w, t);
            }
            return this;
        },
        say: function (word, t) {
            t = t || 100;
            this.w = word;
            var name = this.name;
            this.h = window.setTimeout(function () {
                alert(name + " say: " + word);
            }, t);
            return this;
        }
    };

    var c = new Person(123);
    c.say("i love you").delay(2000);

------解决方案--------------------
JScript code

(function(){

/**
         * @method proxy(Function fn, Object scope, Array args)
         * 创建代理函数，传入一个Function对象，返回该函数的代理函数，并可指定函数内的this 作用域，和函数被调用时的参数
         * 
         * <pre>
         * 1、fn - 被代理的函数 
         * 2、scope - 被代理函