function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

MM_preloadImages('images/menu/hbut_about.gif', 'images/menu/hbut_career.gif', 'images/menu/hbut_contact.gif', 'images/menu/hbut_corp.gif', 'images/menu/hbut_dist.gif', 'images/menu/hbut_events.gif', 'images/menu/hbut_home.gif', 'images/menu/hbut_products.gif', 'images/menu/hbut_support.gif');