detect the div is visivle or not

visible.js

$.fn.inView = function () {
        if (!this.length) return false;
        var rect = this.get(0).getBoundingClientRect();

        return (
            rect.top >= 0 &&
            rect.left >= 0 &&
            rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
            rect.right <= (window.innerWidth || document.documentElement.clientWidth)
        );

    };


    var lastScrollTop = 0;
    $(window).scroll(function (event) {
        var st = $(this).scrollTop();
        if (st > lastScrollTop) {
            // downscroll code
            if ($('.hidden-div').inView()) {
                $(".home-banner-content > .btn").css({
                    'transform': 'translate(-50%,130%)'
                });
            } else {
                $(".home-banner-content > .btn").css({
                    /* 'transform': 'translate(-50%,0)',*/
                    'transition': '0.5s all'
                });
            }

            /*show btn after bottom div*/
            if ($('.show-div').inView()) {
                $(".home-banner-content > .btn").css({
                    'transform': 'translate(-50%,0)'
                });
            }

        } else {
            // upscroll code
            /*hide btn after bottom div*/
            if ($('.show-div').inView()) {
                $(".home-banner-content > .btn").css({
                    'transform': 'translate(-50%,130%)'
                });
            }


            /*show btn after the div is visible*/
            if ($('.timer-block').inView()) {
                $(".home-banner-content > .btn").css({
                    'transform': 'translate(-50%,0)'
                });
            }

        }
        lastScrollTop = st;
    });