js基于对象冒充和原型方式实现继承关系

	Class = function(){
		var subClass = function(){};
		var superClass = arguments[0];
		if(typeof(superClass) === "function"){
			subClass = function(){
				if(this.initialize){
					this.initialize.call(this , arguments);
				}
			};
			subClass.prototype = new superClass();
			subClass.prototype.constructor = subClass;
		}
		subClass.prototype.extend = function(extendsObj){
			for(var m in extendsObj){
				this[m] = extendsObj[m];
			}
		};
		return  subClass;
	};

    SuperClass = Class();
	SuperClass.prototype.extend({
		a : 'superClass field a',
		b : function(){
			return "superClass method b";
		},
		c : 's'
	});

    SubClass = Class(SuperClass);
	SubClass.prototype.extend({
		a : 'subClass field a',
		b : function(){
			return "subClass method b";
		}
	});
	
	var s = new SubClass();
	alert(s.a);
	alert(s.b());
	alert(s.c);