Loader and nav bar

I have a question with a page I'm doing, I made a loader with jquery:

window.onload = function() {
    $(".loader").fadeOut("slow");
    $(".container-fluid").css("display","block");
}

NOW, when the page is loading the nav bar that is inside the container-fluid I guess it is because it is in position:fixed by removing that is solved and does not come out when loading the page, I I would like to know if there is any way to solve this with some jQuery function or something like that. thanks