if (document.images) {

 professionalon = new Image();
 professionalon.src = "/images/menu_professional_on.gif";

 professionaloff = new Image();
 professionaloff.src = "/images/menu_professional_off.gif";

 advertisingon = new Image();
 advertisingon.src = "/images/menu_advertising_on.gif";

 advertisingoff = new Image();
 advertisingoff.src = "/images/menu_advertising_off.gif";

 corporateon = new Image();
 corporateon.src = "/images/menu_corporate_on.gif";

 corporateoff = new Image();
 corporateoff.src = "/images/menu_corporate_off.gif";

 homeon = new Image();
 homeon.src = "/images/menu_home_on.gif";

 homeoff = new Image();
 homeoff.src = "/images/menu_home_off.gif";

 }