if (document.images) {

    home_big_ad_up       = new Image();
    home_big_ad_up.src   = "images/home_big_ad.png" ;
    home_big_ad_down     = new Image() ;
    home_big_ad_down.src = "images/home_big_ad_rollover.png" ;

    home_sign_up_btn_up       = new Image();
    home_sign_up_btn_up.src   = "images/home_sign_up_btn.png" ;
    home_sign_up_btn_down     = new Image() ;
    home_sign_up_btn_down.src = "images/home_sign_up_btn_rollover.png" ;
    
    home_ad_left_up       = new Image();
    home_ad_left_up.src   = "images/home_ad_left.png" ;
    home_ad_left_down     = new Image() ;
    home_ad_left_down.src = "images/home_ad_left_rollover.png" ;

    home_ad_middle_up       = new Image();
    home_ad_middle_up.src   = "images/home_ad_middle.png" ;
    home_ad_middle_down     = new Image() ;
    home_ad_middle_down.src = "images/home_ad_middle_rollover.png" ;

    home_ad_right_up       = new Image();
    home_ad_right_up.src   = "images/home_ad_right.png" ;
    home_ad_right_down     = new Image() ;
    home_ad_right_down.src = "images/home_ad_right_rollover.png" ;
    
    home_etrack_login_btn_up       = new Image();
    home_etrack_login_btn_up.src   = "images/home_etrack_login_btn.png" ;
    home_etrack_login_btn_down     = new Image() ;
    home_etrack_login_btn_down.src = "images/home_etrack_login_btn_rollover.png" ;
  
    home_freight_quote_btn_up       = new Image();
    home_freight_quote_btn_up.src   = "images/home_freight_quote_btn.png" ;
    home_freight_quote_btn_down     = new Image() ;
    home_freight_quote_btn_down.src = "images/home_freight_quote_btn_rollover.png" ;
  
    carrier_login_btn_up       = new Image();
    carrier_login_btn_up.src   = "images/carrier_login_btn.png" ;
    carrier_login_btn_down     = new Image() ;
    carrier_login_btn_down.src = "images/carrier_login_btn_rollover.png" ;
    
    etrack_login_btn_up       = new Image();
    etrack_login_btn_up.src   = "images/etrack_login_btn.png" ;
    etrack_login_btn_down     = new Image() ;
    etrack_login_btn_down.src = "images/etrack_login_btn_rollover.png" ;
    
    pickpup_request_btn_up       = new Image();
    pickpup_request_btn_up.src   = "images/pickpup_request_btn.png" ;
    pickpup_request_btn_down     = new Image() ;
    pickpup_request_btn_down.src = "images/pickpup_request_btn_rollover.png" ;
    
    sign_up_btn_up       = new Image();
    sign_up_btn_up.src   = "images/sign_up_btn.png" ;
    sign_up_btn_down     = new Image() ;
    sign_up_btn_down.src = "images/sign_up_btn_rollover.png" ;

    side_ad_top_up       = new Image();
    side_ad_top_up.src   = "images/side_ad_top.png" ;
    side_ad_top_down     = new Image() ;
    side_ad_top_down.src = "images/side_ad_top_rollover.png" ;

    side_ad_middle_up       = new Image();
    side_ad_middle_up.src   = "images/side_ad_middle.png" ;
    side_ad_middle_down     = new Image() ;
    side_ad_middle_down.src = "images/side_ad_middle_rollover.png" ;

    side_ad_bottom_up       = new Image();
    side_ad_bottom_up.src   = "images/side_ad_bottom.png" ;
    side_ad_bottom_down     = new Image() ;
    side_ad_bottom_down.src = "images/side_ad_bottom_rollover.png" ;
    
    side_content_ad_up       = new Image();
    side_content_ad_up.src   = "images/side_content_ad.png" ;
    side_content_ad_down     = new Image() ;
    side_content_ad_down.src = "images/side_content_ad_rollover.png" ;

}
function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_down.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_up.src" );
    }
}