function switchMenu(num) {
    if (document.getElementById) {
    var myImg = eval("document.getElementById('box" + num + "')");
    var myObj = 'sub' + num;
    var el = document.getElementById(myObj);
        if (el.style.display != 'block') { // if menu is not already opened
/*
            for (var i=0; i<ar.length; i++) {   // loop thru span tags within the masterdiv div tag
                if (ar[i].className == 'submenu') { ar[i].style.display = 'none';   } // if it's a submenu, close menu                          
                var boxImg = eval("document.getElementById('box" + i + "')"); // construct a box image object
                if (boxImg) { boxImg.src = '/images/icons/box_plus.gif'; } // if object exists, set to plus sign
            }
*/
            el.style.display = 'block'; // opens selected menu
            myImg.src = '/images/icons/box_minus.gif';  // set image to minus sign
        } else {
            el.style.display = 'none';  //close menu
            myImg.src = '/images/icons/box_plus.gif';
        }
        } 
}