JavaScript面向对象编程(入门参考)

var plus = function(x,y){   
    document.write( x + ' + ' + y + ' = ' + (x+y) + '<br>');   
    return x + y;   
};   
    
var minus = function(x,y){   
    document.write(x + ' - ' + y + ' = ' + (x-y) + '<br>');   
    return x - y;   
};   
    
var operations = {   
    '+': plus,   
    '-': minus   
};   
    
var calculate = function(x, y, operation){   
    return operations[operation](x, y);   
};   
    
calculate(12, 4, '+');   
calculate(24, 3, '-');  

var Cal = function(x, y){   
    this.x = x;   
    this.y = y;   
}   
    
Cal.prototype.operations = {   
    '+': function(x, y) { return x+y;},   
    '-': function(x, y) { return x-y;}   
};   
    
Cal.prototype.calculate = function(operation){   
    return this.operations[operation](this.x, this.y);   
};   
    
var c = new Cal(4, 5);   
    
c.calculate('+');   
c.calculate('-');  
 

function Person(name, email, website){   
    this.name = name;   
    this.email = email;   
    this.website = website;   
};   
    
Person.prototype.sayHello = function(){   
    var hello = "Hello, I am "+ this.name  + ", <br>" +   
                "my email is: " + this.email + ", <br>" +   
                "my website is: " + this.website;   
    return hello;   
};   
    
function Student(name, email, website, no, dept){   
    var proto = Object.getPrototypeOf;   
    proto(Student.prototype).constructor.call(this, name, email, website);   
    this.no = no;   
    this.dept = dept;   
}   
    
// 继承prototype   
Student.prototype = Object.create(Person.prototype);   
    
//重置构造函数   
StudentStudent.prototype.constructor = Student;   
    
//重载sayHello()   
Student.prototype.sayHello = function(){   
    var proto = Object.getPrototypeOf;   
    var hello = proto(Student.prototype).sayHello.call(this) + '<br>';   
    hello += "my student no is: " + this. no + ", <br>" +   
             "my departent is: " + this. dept;   
    return hello;   
};   
    
var me = new Student(   
    "Chen Hao",   
    "haoel@hotmail.com",   
    "http://www.jb200.com",   
    "12345678",   
    "Computer Science"   
);   
document.write(me.sayHello());  

Object.create ()函数
function clone(proto) {   
    function Dummy() { }   
    
    Dummy.prototype             = proto;   
    DummyDummy.prototype.constructor = Dummy;   
    
    return new Dummy(); //等价于Object.create(Person);   
}   
    
var me = clone(Person);  

defineProperty ()函数
function defineProperty(target, key, descriptor) {   
    if (descriptor.value){   
        target[key] = descriptor.value;   
    }else {   
        descriptor.get && target.__defineGetter__(key, descriptor.get);   
        descriptor.set && target.__defineSetter__(key, descriptor.set);   
    }   
    
    return target   
}  
 
keys ()函数
function keys(object) { var result, key   
    result = [];   
    for (key in object){   
        if (object.hasOwnProperty(key))  result.push(key)   
    }   
    
    return result;   
}  

Object.getPrototypeOf() 函数
function proto(object) {   
    return !object?                null   
         : '__proto__' in object?  object.__proto__   
         : /* not exposed? */      object.constructor.prototype   
}  
 
 
bind函数
var slice = [].slice   
function bind(fn, bound_this) { var bound_args   
    bound_args = slice.call(arguments, 2)   
    return function() { var args   
        args = bound_args.concat(slice.call(arguments))   
        return fn.apply(bound_this, args) }   
}