pic1on = new Image( );
       pic1on.src = "images/nav_sub_address_roll.gif";
       pic2on = new Image( );
       pic2on.src = "images/nav_sub_admissions_roll.gif";
       pic3on = new Image( );
       pic3on.src = "images/nav_sub_college_roll.gif";
       pic4on = new Image( );
       pic4on.src = "images/nav_sub_contact_roll.gif";
       pic5on = new Image( );
       pic5on.src = "images/nav_sub_handbook_roll.gif";
       pic6on = new Image( );
       pic6on.src = "images/nav_sub_interviews_roll.gif";
       pic7on = new Image( );
       pic7on.src = "images/nav_sub_membership_roll.gif";
       pic8on = new Image( );
       pic8on.src = "images/nav_sub_catalog_roll.gif";
       pic9on = new Image( );
       pic9on.src = "images/nav_sub_receptions_roll.gif";
       pic10on = new Image( );
       pic10on.src = "images/nav_sub_training_roll.gif";
       pic11on = new Image( );
       pic11on.src = "images/nav_sub_updates_roll.gif";
       pic12on = new Image( );
       pic12on.src = "images/topnav_nasc_roll.gif";
       pic13on = new Image( );
       pic13on.src = "images/topnav_alumni_roll.gif";
       pic14on = new Image( );
       pic14on.src = "images/topnav_admissions_roll.gif";
       pic15on = new Image( );
       pic15on.src = "images/topnav_jhu_roll.gif";

       pic1off = new Image( );
       pic1off.src = "images/nav_sub_address.gif";
       pic2off = new Image( );
       pic2off.src = "images/nav_sub_admissions.gif";
       pic3off = new Image( );
       pic3off.src = "images/nav_sub_college.gif";
       pic4off = new Image( );
       pic4off.src = "images/nav_sub_contact.gif";
       pic5off = new Image( );
       pic5off.src = "images/nav_sub_handbook.gif";
       pic6off = new Image( );
       pic6off.src = "images/nav_sub_interviews.gif";
       pic7off = new Image( );
       pic7off.src = "images/nav_sub_membership.gif";
       pic8off = new Image( );
       pic8off.src = "images/nav_sub_catalog.gif";
       pic9off = new Image( );
       pic9off.src = "images/nav_sub_receptions.gif";
       pic10off = new Image( );
       pic10off.src = "images/nav_sub_training.gif";
       pic11off = new Image( );
       pic11off.src = "images/nav_sub_updates.gif";
       pic12off = new Image( );
       pic12off.src = "images/topnav_nasc.gif";
       pic13off = new Image( );
       pic13off.src = "images/topnav_alumni.gif";
       pic14off = new Image( );
       pic14off.src = "images/topnav_admissions.gif";
       pic15off = new Image( );
       pic15off.src = "images/topnav_jhu.gif";
       
  function img_act (imgName)   {
      imgOn = eval (imgName + "on.src");
      document [imgName].src = imgOn;
      }

  function img_inact (imgName)   {
      imgOff = eval (imgName + "off.src");
      document [imgName].src = imgOff;
      }

function showRatings(layername)
    {
        var layer1 = document.getElementById('hopkins');
        layer1.style.visibility = "hidden"
        var obj = document.getElementById(layername);
        obj.style.visibility = "visible";
    }

function hideRatings(layername)
    {
        var obj = document.getElementById(layername);
        obj.style.visibility = "hidden";
    }