https://www.servsafe.com/access/Scripts/Impersonation/impersonation-status.js

1$(function () {
2    var impersonateCheckInterval = 5000;
3    var impersonateScript = $('[data-purpose="impersonate"]')
4    var baseUrl = $(impersonateScript).attr('data-root-url');
5    var numRequests = 0;
6
7    if (baseUrl && baseUrl.slice(-1) !== '/') {
8        baseUrl = baseUrl + '/';
9    }
10
11    var pollUrl = baseUrl + 'Impersonation/PollSession';
12    var impersonationData = null;
13
14    var create = function () {
15        var html =
16            '<div id="impersonate-status" class="impersonate-panel">' +
17            '<span class="impersonate-title">Impersonating User</span>' +
18            '<p id="impersonate-user"></p>' +
19            '</div>';
20
21        return $(html);
22    };
23
24    var overlay = function () {
25        var html =
26                '<div id="impersonate-overlay-single" class="impersonate-overlay">' +
27                    '<div class="impersonate-overlay-message-container">' +
28                        '<p class="impersonate-overlay-message">' +
29                            'This browser window has been deactivated because your session ' +
30                            'has timed out or you have impersonated a different user.' +
31                        '</p>' +
32                    '</div>' +
33                '</div>';
34        return $(html);
35    };
36
37    // ERROR Setup
38    $(document).ajaxError(function (event, jqxhr, settings) {
39        if (settings.url === pollUrl) {
40            /* Give two attempts to find an impersonation context, if not, then stop polling. */
41            if (numRequests < 2 && jqxhr.status === 404) {
42                // Check again in 250ms
43                setTimeout(checkImpersonationState, 250);
44            }
45        }
46    });
47
48    var handleImpersonationResponse = function (data) {
49        if (typeof (data) === 'string') {
50            data = JSON.parse(data);
51        }
52
53        if (!impersonationData) {
54            impersonationData = data;
55        }
56
57        if (impersonationData.ImpersonatingUser !== data.ImpersonatingUser
58            || impersonationData.Hash !== data.Hash) {
59
60            var overlayElement = overlay();
61            $('body').append(overlayElement);
62            $('#impersonate-overlay-single').show();
63
64            // Return early if status check fails or indicates a different user being impersonated.
65            return;
66        }
67
68        var dataElement = $('#impersonate-status');
69        if (dataElement.length === 0) {
70            var element = create();
71            element.find('#impersonate-user').text(data.ImpersonatingUser);
72            $('body').append(element);
73        }
74
75        // This will only check again, if the status was polled and the impersonation status is still valid.
76        setTimeout(checkImpersonationState, impersonateCheckInterval);
77    };
78
79    var checkImpersonationState = function () {
80        numRequests++;
81        $.get(pollUrl, handleImpersonationResponse);
82    };
83
84    // This will execute the initial call in a separate "thread" that won't block execution of the rest of the page.
85    setTimeout(checkImpersonationState, 0);
86});