function DisplayControl(display){
	this.lastDisplayed = null
	this.show(display)
}

DisplayControl.prototype.show = function (id) {
	var obj = document.getElementById(id)
	
	if (obj && String(typeof obj.style).toLowerCase() == "object") { 
		obj.style.display = "block"
		this.lastDisplayed = id;
		return true
	}
	return false
}

DisplayControl.prototype.hide = function (id) {
	var obj = document.getElementById(id)
		
	if (obj && String(typeof obj.style).toLowerCase() == "object") { 
		obj.style.display = "none"
		return true
	}
	return false
}

DisplayControl.prototype.swapDisplay = function (id) {
	this.hide(this.lastDisplayed)
	this.show(id)
}