Stacks (Solution)

stacks.js

var Stack = function(){
	this.storage = {};
	this.count = 0;
};

Stack.prototype.push = function(val) {
	this.storage[this.count++] = val;
	return this.count;
}

Stack.prototype.pop = function() {
	var value = this.storage[--this.count];
	delete this.storage[this.count];

	if (this.count < 0) {
	    this.count = 0;
	}

	return value;
}

Stack.prototype.size = function() {
	return this.count;
}

var myWeeklyMenu = new Stack();
myWeeklyMenu.push("Coffee");
myWeeklyMenu.push("Rice");
myWeeklyMenu.push("Cold Drink");
myWeeklyMenu.pop();
myWeeklyMenu.size();

Please feel free to ask me about my answer gist. :)