javascript里的继承

 1 function extend(subClass, superClass){
 2     var F = function(){};
 3     F.prototype = superClass.prototype;
 4     subClass.prototype = new F();
 5     subClass.prototype.constructor = subClass;
 6 
 7     subClass.superclass = superClass.prototype; // optional
 8     if (superClass.prototype.constructor == Object.prototype.constructor){
 9         superClass.prototype.constructor = superClass;
10     }  
11 }

function clone(object){
    function F(){}
    F.prototype = object;
    return new F();
}