原型链的继承

//圣杯模式
function inherit(Target,Origin){
    function F(){};
    Target.prototype = new F();
    F.prototype = Origin.prototype;
    Target.prototype.constructor = Target;
    Target.prototype.uber = Origin.prototype;
}

//雅虎 YUI3
var inherit = (function(){
    var F = function(){};
    return function(Target,Origin){
        F.prototype = Origin.prototype;
        Target.prototype = new F();
        Target.prototype.constructor = Target;
        Target.prototype.uber = Origin.prototype;
    }
})