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