Back To Top

 1 //scroll to top
 2 (function ($) {
 3     $.fn.backTop = function () {
 4         var backBtn = this;
 5 
 6         var position = 1000;
 7         var speed = 900;
 8 
 9         $(document).scroll(function () {
10             var pos = $(window).scrollTop();
11 
12             if (pos >= position) {
13                 backBtn.fadeIn(speed);
14             } else {
15                 backBtn.fadeOut(speed);
16             }
17         });
18 
19         backBtn.click(function () {
20             $("html, body").animate({ scrollTop: 0 }, 900);
21         });
22     }
23 }(jQuery));

 <a id="backTop" class="btn btn-back-top bg-teal"></a>