[rnd me]

function PasswordLogin(folder)
{
    var filename = folder+"/" + document.formlogin.trackingnr.value.toUpperCase() + ".html";
    // ...

then,

PasswordLogin("transactions");
PasswordLogin("stock");

you probably want to remove the alert since one will fail.

you can make an additional progress monitor to throw the alert up if both fail:

function doPageSearch(){
  doPageSearch.tries=2; // how may folders to search?
  PasswordLogin("transactions");
  PasswordLogin("stock");
}

then change

else
            {
                alert('Votre Numero est errone. Merci de reessayer!');
                return false;
            }

to

else
            {
 
                if(! --doPageSearch.tries)  alert('Votre Numero est errone. Merci de reessayer!');
                return false;
            }