https://www.sherry4x4.com/wp-content/plugins/automotive/js/jquery.parallax.js?ver=18.8

1(function($) {
2  "use strict";
3
4    $.fn.parallax = function(options) {
5
6        var windowHeight = $(window).height();
7		
8        var settings = $.extend({
9            velocity: 0.15,
10			offset:   0
11        }, options);
12
13        return this.each(function() {
14
15            var element    = $(this);
16			var velocity   = ($(this).data("velocity") ? $(this).data("velocity") : settings.velocity);
17			var img_offset = ($(this).data("offset") ? $(this).data("offset") : settings.offset);
18			var no_repeat  = ($(this).data("no-repeat") ? $(this).data("no-repeat") : false);
19
20			// background image
21			if($(this).data('image')){
22				$(this).css("background-image", "url(" + $(this).data('image') + ")");
23			}
24
25            // if no repeat is set then get height
26            if(no_repeat){
27                var image_url = $(element).css("background-image").replace('url(','').replace(')','');
28                $("<img/>").attr("src", image_url).load(function() {
29                    image_height = this.height;
30                    div_height   = element.height();
31                });
32            }
33
34            $(document).scroll(function() {
35
36                var scrollTop  = $(window).scrollTop();
37                var offset     = element.offset().top;
38                var out_height = element.outerHeight();
39				var height     = $(window).height();
40
41                if (offset + out_height <= scrollTop || offset >= scrollTop + windowHeight) {
42                    return;
43                }
44
45                //var new_position = Math.round(((offset - (scrollTop + height)) * velocity) + img_offset);
46                var new_position = Math.round(((scrollTop + ( height - offset ) ) * velocity) + img_offset);
47
48                if((typeof image_height != "undefined") && (Math.abs(new_position) + div_height) > image_height){
49                    return;
50                }
51
52                element.css('background-position', '50% ' + new_position + 'px');
53
54            });
55        });
56    }
57})(jQuery);