var offset=0;
var browser=(((navigator.appName=="Netscape")&&(parseInt(navigator.appVersion)>=4))||
((navigator.appName=="Microsoft Internet Explorer")&&(parseInt(navigator.appVersion)>=4)))


if (browser){
        bt1a=new Image();       bt1b=new Image();
        bt2a=new Image();       bt2b=new Image();
        bt3a=new Image();       bt3b=new Image();
        bt4a=new Image();       bt4b=new Image();
        bt5a=new Image();       bt5b=new Image();
        bt6a=new Image();       bt6b=new Image();
        bt7a=new Image();       bt7b=new Image();
        bt8a=new Image();       bt8b=new Image();
        bt9a=new Image();       bt9b=new Image();

        bt1a.src="images/bt_home.gif";         bt1b.src="images/bt_home_c.gif";
        bt2a.src="images/bt_abou.gif";         bt2b.src="images/bt_abou_c.gif";
        bt3a.src="images/bt_staf.gif";         bt3b.src="images/bt_staf_c.gif";
        bt4a.src="images/bt_serv.gif";         bt4b.src="images/bt_serv_c.gif";
        bt5a.src="images/bt_test.gif";         bt5b.src="images/bt_test_c.gif";
        bt6a.src="images/bt_cont.gif";         bt6b.src="images/bt_cont_c.gif";
        bt7a.src="images/bt_prin.gif";         bt7b.src="images/bt_prin_c.gif";
        bt8a.src="images/bt_link.gif";         bt8b.src="images/bt_link_c.gif";
        bt9a.src="images/bt_fina.gif";         bt9b.src="images/bt_fina_c.gif";
}

function show(num){
        if (browser){
                        if (num=="1")  document.images.home.src=bt1a.src;
                        if (num=="10") document.images.home.src=bt1b.src;
                        if (num=="2")  document.images.about.src=bt2a.src;
                        if (num=="20") document.images.about.src=bt2b.src;
                        if (num=="3")  document.images.staff.src=bt3a.src;
                        if (num=="30") document.images.staff.src=bt3b.src;
                        if (num=="4")  document.images.services.src=bt4a.src;
                        if (num=="40") document.images.services.src=bt4b.src;
                        if (num=="5")  document.images.tests.src=bt5a.src;
                        if (num=="50") document.images.tests.src=bt5b.src;
                        if (num=="6")  document.images.contact.src=bt6a.src;
                        if (num=="60") document.images.contact.src=bt6b.src;
                        if (num=="7")  document.images.forms.src=bt7a.src;
                        if (num=="70") document.images.forms.src=bt7b.src;
                        if (num=="8")  document.images.links.src=bt8a.src;
                        if (num=="80") document.images.links.src=bt8b.src;
                        if (num=="9")  document.images.financial.src=bt9a.src;
                        if (num=="90") document.images.financial.src=bt9b.src;                       
        }
}