if (document.images) {
  var nav_H_off = new Image();
  nav_H_off.src = "images/nav_H_1.png";
  var nav_H_on = new Image();
  nav_H_on.src = "images/nav_H_2.GIF";

  var nav_C_off = new Image();
  nav_C_off.src = "images/nav_C_1.png";
  var nav_C_on = new Image();
  nav_C_on.src = "images/nav_C_2.GIF";

  var nav_T_off = new Image();
  nav_T_off.src = "images/nav_T_1.png";
  var nav_T_on = new Image();
  nav_T_on.src = "images/nav_T_2.GIF";

  var nav_A_off = new Image();
  nav_A_off.src = "images/nav_A_1.png";
  var nav_A_on = new Image();
  nav_A_on.src = "images/nav_A_2.GIF";

  var nav_F_off = new Image();
  nav_F_off.src = "images/nav_F_1.png";
  var nav_F_on = new Image();
  nav_F_on.src = "images/nav_F_2.GIF";

  var A_email_off = new Image();
  A_email_off.src = "images/A_email_1.GIF";
  var A_email_on = new Image();
  A_email_on.src = "images/A_email_2.GIF";

  var A_web_off = new Image();
  A_web_off.src = "images/A_web_1.GIF";
  var A_web_on = new Image();
  A_web_on.src = "images/A_web_2.GIF";

  var N_home_off = new Image();
  N_home_off.src = "images/N_home_1.GIF";
  var N_home_on = new Image();
  N_home_on.src = "images/N_home_2.GIF";

  var C_SH_off = new Image();
  C_SH_off.src = "images/N_catalogus_1.GIF";
  var C_SH_on = new Image();
  C_SH_on.src = "images/N_catalogus_2.GIF";

  var C_FT_off = new Image();
  C_FT_off.src = "images/N_catalogus_1.GIF";
  var C_FT_on = new Image();
  C_FT_on.src = "images/N_catalogus_2.GIF";

  var T_SH_off = new Image();
  T_SH_off.src = "images/N_info_1.GIF";
  var T_SH_on = new Image();
  T_SH_on.src = "images/N_info_2.GIF";

  var FT_vorige_off = new Image();
  FT_vorige_off.src = "images/N_vorige_1.GIF";
  var FT_vorige_on = new Image();
  FT_vorige_on.src = "images/N_vorige_2.GIF";

  var FT_up_off = new Image();
  FT_up_off.src = "images/N_omhoog_1.GIF";
  var FT_up_on = new Image();
  FT_up_on.src = "images/N_omhoog_2.GIF";

  var FT_volgende_off = new Image();
  FT_volgende_off.src = "images/N_volgende_1.GIF";
  var FT_volgende_on = new Image();
  FT_volgende_on.src = "images/N_volgende_2.GIF";

}

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

function deactivate(imgName) {
  if (document.images) {
    if ( eval(imgName + "_off.complete") ) {
      document.images[imgName].src = eval(imgName + "_off.src");
    }
  }
}