if (document.images) {
  btn_what_we_believe = new Image();
  btn_what_we_believe.src = theme_root + "images/btn-what_we_believe.jpg";
  btn_what_we_believe_on = new Image();
  btn_what_we_believe_on.src = theme_root + "images/btn-what_we_believe-on.jpg";
  
  btn_our_plan = new Image();
  btn_our_plan.src = theme_root + "images/btn-our_plan.jpg";
  btn_our_plan_on = new Image();
  btn_our_plan_on.src = theme_root + "images/btn-our_plan-on.jpg";
  
  btn_join_us = new Image();
  btn_join_us.src = theme_root + "images/btn-join_us.jpg";
  btn_join_us_on = new Image();
  btn_join_us_on.src = theme_root + "images/btn-join_us-on.jpg";
  
  btn_contact_us = new Image();
  btn_contact_us.src = theme_root + "images/btn-contact_us.jpg";
  btn_contact_us_on = new Image();
  btn_contact_us_on.src = theme_root + "images/btn-contact_us-on.jpg";
  
  btn_archives = new Image();
  btn_archives.src = theme_root + "images/btn-archives.jpg";
  btn_archives_on = new Image();
  btn_archives_on.src = theme_root + "images/btn-archives-on.jpg";
  
  btn_help_by_donating = new Image();
  btn_help_by_donating.src = theme_root + "images/btn-help_by_donating.jpg";
  btn_help_by_donating_on = new Image();
  btn_help_by_donating_on.src = theme_root + "images/btn-help_by_donating-on.jpg";
  
  btn_become_a_member = new Image();
  btn_become_a_member.src = theme_root + "images/btn-become_a_member.jpg";
  btn_become_a_member_on = new Image();
  btn_become_a_member_on.src = theme_root + "images/btn-become_a_member-on.jpg";
  
  btn_volunteer_today = new Image();
  btn_volunteer_today.src = theme_root + "images/btn-volunteer_today.jpg";
  btn_volunteer_today_on = new Image();
  btn_volunteer_today_on.src = theme_root + "images/btn-volunteer_today-on.jpg";
 
  btn_write_with_us = new Image();
  btn_write_with_us.src = theme_root + "images/btn-write_with_us.jpg";
  btn_write_with_us_on = new Image();
  btn_write_with_us_on.src = theme_root + "images/btn-write_with_us-on.jpg";
   
  btn_home_us = new Image();
  btn_home.src = theme_root + "images/btn-home.jpg";
  btn_home_on = new Image();
  btn_home_on.src = theme_root + "images/btn-home-on.jpg";
}

function switchOn(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + "_on.src");
    }
}
  
function switchOff(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + ".src");
    }
}