//function to display or hide a given element
    function showHideItemsPM(myItem, plusMinus){
    //this is the ID of the hidden item
    var myItem = document.getElementById(myItem);
    //this is the ID of the plus/minus button image
    var plusMinus = document.getElementById(plusMinus);
        if (myItem.style.display != "none") {
            //items are currently displayed, so hide them
            myItem.style.display = "none";
            swapImagePM(plusMinus,"plus");
        }
        else {
            //items are currently hidden, so display them
            myItem.style.display = "block";
            swapImagePM(plusMinus,"minus");
        }
    }

    //function to swap an image based on its current state
    function swapImagePM(myImage, state) {
        if (state == "minus") {
            myImage.src = "/images/common/minus.gif";
        }
        else {
            myImage.src = "/images/common/plus.gif";
    	}
	}