javascript 继承方式（4）

/**
* @param {String} className
* @param {String/Function} superClass
* @param {Function} classImp
*/
function $class(className, superClass, classImp){
if(superClass === "") superClass = Object;
var clazz = function(){
return function(){
if(typeof this.init == "function"){
this.init.apply(this, arguments);
}
};
}();
var p = clazz.prototype = new superClass();
var _super = superClass.prototype;
window[className] = clazz;
classImp.apply(p, [_super]);
}

/**
* 父类 Person
*/
$class('Person','',function(){
this.init = function(name){
this.name = name;
};
this.getName = function(){
return this.name;
};
this.setName = function(name){
this.name = name;
}
});

/**
 * 子类 Man
 */
$class('Man', Person, function(supr){
    this.init = function(name, age){
        supr.init.apply(this,[name]); // 该句很重要
        this.age = age;
    };
    this.getAge = function(){
        return this.age;
    };
    this.setAge = function(age){
        this.age = age;
    };
});
var m = new Man('Jack',25);
console.log(m.name); // Jack
console.log(m.age); // 25