Something

			// Plus button controller
			this.plusButton = new Element('div');
			this.plusButton.addEvent('mouseover', this.controllerMouseOverHandler.bind(this));
			this.plusButton.addEvent('mouseout', this.controllerMouseOutHandler.bind(this));
			this.plusButton.addEvent('click', this.plusClickHandler.bind(this));
			
			// Minus button controller
			this.minusButton = new Element('div');
			
			this.minusButton.addEvent('mouseover', this.controllerMouseOverHandler.bind(this));
			this.minusButton.addEvent('mouseout', this.controllerMouseOutHandler.bind(this));
			this.minusButton.addEvent('click', this.minusClickHandler.bind(this));
			
			// Append elements
			this.plusButton.inject(this.container);
			this.numberDisplayContainer.inject(this.container);
			this.minusButton.inject(this.container);
			
			// Inject in document
			this.container.inject(this.target.getParent());