$(window).scroll(function() {
Center1block = $("#block-1").offset().top - ( $(window).height() - divHeight )/2;
Bottom1block = $("#block-1").offset().top - $(window).height();
Top1block = $("#block-1").offset().top + divHeight;

if(getScrollTop() > Bottom1block && getScrollTop() < Top1block){
$("#block-1 .txt").css('marginTop', ( (getScrollTop() - Center1block) *0.3) + 'px');
        }
}

$(window).scroll(function() {
    Center1block = $("#block-1").offset().top - ( $(window).height() - divHeight )/2;
    Bottom1block = $("#block-1").offset().top - $(window).height();
    Top1block = $("#block-1").offset().top + divHeight;

    if(getScrollTop() > Bottom1block && getScrollTop() < Top1block){
    $("#block-1 .txt").css('marginTop', ( (getScrollTop() ) *0.3) + 'px');
            }

    Center2block = $("#block-2").offset().top - ( $(window).height() - divHeight )/2;
    Bottom2block = $("#block-2").offset().top - $(window).height();
    Top2block = $("#block-2").offset().top + divHeight;

    if(getScrollTop() > Bottom2block && getScrollTop() < Top2block){
    $("#block-2 .txt").css('marginTop', ( (getScrollTop() - Center2block) *0.3) + 'px');
            }

    Center3block = $("#block-3").offset().top - ( $(window).height() - divHeight )/2;
    Bottom3block = $("#block-3").offset().top - $(window).height();
    Top3block = $("#block-3").offset().top + divHeight;

    if(getScrollTop() > Bottom3block && getScrollTop() < Top3block){
    $("#block-3 .txt").css('marginTop', ( (getScrollTop() - Center3block) *0.3) + 'px');
            }
    }

$(window).scroll(function () {
    var win_height = $(window).height();
    var scroll_top = getScrollTop();
    $(".class").each(function () {
        var off_top = $(this).offset().top;
        var Center1block = off_top - ( win_height - divHeight )/2;
        var Bottom1block = off_top - win_height;
        var Top1block = off_top + divHeight;

        if (scroll_top > Bottom1block && scroll_top < Top1block){
            $(this).find(".txt").css('marginTop', ( (scroll_top ) *0.3) + 'px');
        }
    });
});