function showHideItems(myItem, myButton){
	
	//this is the ID of the hidden item
	var myItem = document.getElementById(myItem);	
	//var myButton = document.getElementById(myButton);

	if (myItem.style.display != "none") {
	//items are currently displayed, so hide them
	myItem.style.display = "none";

	swapImage(myButton,"plus");
	}
	else {
	//items are currently hidden, so display them
	myItem.style.display = "block";

	swapImage(myButton,"minus");
	}
}

//function to swap an image based on its current state
function swapImage(myImage, state) {
	var myImage1 = document.getElementById(myImage);
	if (state == "minus") {
		myImage1.src = "../images/minus.gif";		
	}

	else {	
		myImage1.src = "../images/plus.gif";
	}
}