function toggleDisplay (elem){
var head = document.getElementById (elem);
var node = document.getElementById (elem.split ("-") [0] + "-content");
var hide = document.getElementById (elem.split ("-") [0] + "-hide");
var show = document.getElementById (elem.split ("-") [0] + "-show");
    if (node.style.display == "none") {
        node.style.display = "block";
        head.className = "accordion_headings highlight";
        hide.style.display = "inline";
        show.style.display = "none";
    } else if (node.style.display == "block") {
        node.style.display = "none";
        head.className = "accordion_headings";
        hide.style.display = "none";
        show.style.display = "inline";
    } else {
       node.style.display = "none";
       head.className = "accordion_headings";
       hide.style.display = "none";
       show.style.display = "inline";
    }
}