//
// menu_ops.js -- Contains the functions required to facilitate
//   onmouseover/onmouseout behavior for menu items, and to toggle
//   open/closed state for sub-menus.
// EVERY page in the NDPC/N site must include this Javascript file,
//   in order for their menus to function properly.
//
      function highlight( id ) {
        li = "li_" + id;
        liElement = document.getElementById(li);
        if( liElement ) {
          liElement.className = "highlight";
        }
        ae = "a_" + id;
        aElement = document.getElementById(ae);
        if( aElement ) {
          aElement.className = "highlight";
        }
      }

      function unhighlight( id ) {
        li = "li_" + id;
        liElement = document.getElementById(li);
        if( liElement ) {
          liElement.className = "unhighlight";
        }
        ae = "a_" + id;
        aElement = document.getElementById(ae);
        if( aElement ) {
          aElement.className = "unhighlight";
        }
      }

      function toggle( id ) {
        ul = "ul_" + id;
        img = "img_" + id;
        ulElement = document.getElementById(ul);
        imgElement = document.getElementById(img);
        if( ulElement ) {
          if( ulElement.className == 'subclosed' ) {
            ulElement.className = "subopen";
            imgElement.src = "http://www.dropoutprevention.org/images/opened.gif";
          }
          else {
            ulElement.className = "subclosed";
            imgElement.src = "http://www.dropoutprevention.org/images/closed.gif";
          }
        }
      }