https://royaldoor.com/wp-content/plugins/Conversion%20Source%20Plugin/assets/js/source-input.js?ver=7.0.5

1(function () {
2    // https://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
3    function getParameterByName(name, url) {
4        if (!url) url = window.location.href;
5        name = name.replace(/[\[\]]/g, "\\$&");
6        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
7            results = regex.exec(url);
8        if (!results) return null;
9        if (!results[2]) return '';
10        return decodeURIComponent(results[2].replace(/\+/g, " "));
11    }
12
13    function checkForSource(sources) {
14        var str = window.location.href;
15
16        for (var i = 0; i < sources.length; i++) {
17            var source = sources[i];
18
19            if (source.pattern.type === 'getQuery') {
20
21                if (getParameterByName(source.pattern.key)) {
22
23                    if (!source.pattern.value || getParameterByName(source.pattern.key) === source.pattern.value) {
24                        sessionStorage.setItem('source_value', source.name + ': ' + source.pattern.key + '=' + getParameterByName(source.pattern.key));
25                    }
26                }
27            }
28        }
29    }
30
31    function updateSourceInput() {
32        var input = document.getElementsByClassName('gfsi_source');
33
34        if (input.length > 0 && sessionStorage.getItem('source_value')) {
35            input[0].value = sessionStorage.getItem('source_value');
36        }
37    }
38
39    checkForSource(gfsiSources);
40    updateSourceInput();
41})();