Function.prototype.after=function(fn){
var self=this;
return function(){
var ret=self.apply(this,arguments);
if(ret==='nextSuccessor'){
return fn.apply(this,arguments);
}
return ret;
}
};
var order=order500yuan.after(order200yuan).after(orderNormal);
order(1,true,500);
order(1,false,500);