leaderIndex = -1;
function nextLeader() {
    if(leaderIndex>=0) $('#leader'+leaderIndex).hide();
    if(leaderIndex==banners-1) leaderIndex=0;
    else leaderIndex=leaderIndex+1;
    $('#leader'+leaderIndex).show();
    setTimeout(nextLeader, 5000);
}
$(function() {
    nextLeader();
});