https://gatesopenresearch.org/js/shared_scripts/url_handlers.js

1//  HERES A SIMPLE JQUERY EXTENSION TO GET THE PARAMETERS FROM THE REQUEST PARAMETER (URL)
2//  IT RETURNS AN ARRAY CONTAINING A NUMBER OF NAME/VALUE PAIRS
3//  IF WE HAD A URL LIKE... https://f1000research.com/experts?topicIds=1,2&subtopicIds=12
4//
5//  var objParameters = $.getURLParameters();
6//      RETURN VALUE: ["topicIds", "subtopicIds", topicIds: "1,2", subtopicIds: "12"] 
7//
8//  var objParameters = $.getURLParametersJSON();
9//      RETURN VALUE: [Object, Object] / Object[1]: parameterName: topicIds, parameterValue: 1,2
10//
11//  var parameterValue = $.getURLParameterValue("topicIds");
12//      RETURN VALUE: 1,2
13$.extend({
14    getURLParameters: function() {
15        var params = [],
16            currentParam = "",
17            URLString = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&'),
18            i = 0;
19        for (i = 0; i < URLString.length; i++) {
20            currentParam = URLString[i].split('=');
21            params.push(currentParam[0]);
22            params[currentParam[0]] = currentParam[1];
23        }
24        return params;
25    },
26    getURLParametersJSON: function(queryString) {
27        var params = [],
28            queryString = typeof queryString === 'undefined' ? window.location.search : queryString;
29            currentParam = "",
30            URLString = queryString.replace(/^\?/,""),
31            i = 0;
32
33        if(URLString.trim() === "") {
34            return [];
35        }
36
37        var URLParams = URLString.split("&");
38
39        for (i = 0; i < URLParams.length; i++) {
40            currentParam = URLParams[i].split('=');
41            params[i] = { "parameterName": currentParam[0], "parameterValue": currentParam[1] };
42        }
43        return params;
44    },
45    getURLParameterValue: function(name) {
46        return $.getURLParameters()[name];
47    },
48    setURLParameter: function(name, value, queryString) {
49        queryString = typeof queryString === 'undefined' ? window.location.search : queryString;
50
51        var params = $.getURLParametersJSON(queryString);
52
53        var updatedParams = params
54
55            // Remove existing paramter, if it's there
56            .filter(function(param) {
57                return param.parameterName && param.parameterValue && param.parameterName !== name;
58            })
59
60            // Add the new paramter
61            // Or not, if the parameter value is empty
62            .concat(value ? [{ parameterName: name, parameterValue: value }] : [])
63
64            // Encode all the URI's and convert to key=value
65            .map(function(param) {
66                return param.parameterName + "=" + param.parameterValue;
67            })
68            .join("&");
69
70        return updatedParams;
71    }
72});