https://nationformarriage.org/wp-content/themes/politicalwp/js/jquery.parallax-1.1.3.js?ver=1.1.3

1/*
2Plugin: 8. jQuery Parallax
3Version 1.1.3
4Author: Ian Lunn
5Twitter: @IanLunn
6Author URL: http://www.ianlunn.co.uk/
7Plugin URL: http://www.ianlunn.co.uk/plugins/jquery-parallax/
8
9Dual licensed under the MIT and GPL licenses:
10http://www.opensource.org/licenses/mit-license.php
11http://www.gnu.org/licenses/gpl.html
12*/
13
14(function( $ ){
15    var $window = $(window);
16    var windowHeight = $window.height();
17
18    $window.resize(function () {
19        windowHeight = $window.height();
20    });
21
22    $.fn.parallax = function(xpos, speedFactor, outerHeight) {
23        var $this = $(this);
24        var getHeight;
25        var firstTop;
26        var paddingTop = 0;
27        
28        //get the starting position of each element to have parallax applied to it      
29        $this.each(function(){
30            firstTop = $this.offset().top;
31        });
32
33        if (outerHeight) {
34            getHeight = function(jqo) {
35                return jqo.outerHeight(true);
36            };
37        } else {
38            getHeight = function(jqo) {
39                return jqo.height();
40            };
41        }
42            
43        // setup defaults if arguments aren't specified
44        if (arguments.length < 1 || xpos === null) xpos = "50%";
45        if (arguments.length < 2 || speedFactor === null) speedFactor = 0.1;
46        if (arguments.length < 3 || outerHeight === null) outerHeight = true;
47        
48        // function to be called whenever the window is scrolled or resized
49        function update(){
50            var pos = $window.scrollTop();              
51
52            $this.each(function(){
53                var $element = $(this);
54                var top = $element.offset().top;
55                var height = getHeight($element);
56
57                // Check if totally above or totally below viewport
58                if (top + height < pos || top > pos + windowHeight) {
59                    return;
60                }
61
62                $this.css('backgroundPosition', xpos + " " + Math.round((firstTop - pos) * speedFactor) + "px");
63            });
64        }       
65
66        $window.bind('scroll', update).resize(update);
67        update();
68    };
69})(jQuery);