https://www.kino-freistadt.at/instagram-crash-guard.js

1/**
2 * Instagram In-App Browser Crash Guard
3 *
4 * Instagram's PageTranslationRequiredListener.js tries to access window.webkit.messageHandlers
5 * but crashes when it's undefined. This guard provides a safe stub to prevent crashes.
6 *
7 * Issue: TypeError: undefined is not an object (evaluating 'window.webkit.messageHandlers')
8 * Browser: Instagram 400.1.0+ on iOS
9 *
10 * Served as a static external script (see src/components/InstagramCrashGuard.tsx) so it can run
11 * via next/script's "beforeInteractive" strategy without React 19's inline-script warning.
12 */
13(function () {
14    try {
15        // Instagram In-App Browser detection
16        var isInstagram = /Instagram/i.test(navigator.userAgent);
17
18        if (isInstagram && typeof window !== 'undefined') {
19            // Polyfill window.webkit.messageHandlers to prevent Instagram's script from crashing
20            if (!window.webkit) {
21                // noinspection JSConstantReassignment
22                window.webkit = {};
23            }
24            if (!window.webkit.messageHandlers) {
25                window.webkit.messageHandlers = {};
26            }
27
28            // Stub for Instagram's translation handlers
29            ['IABTranslationJS', 'IABUserAgentLanguageDetectionJS'].forEach(function (handler) {
30                if (!window.webkit.messageHandlers[handler]) {
31                    window.webkit.messageHandlers[handler] = {
32                        postMessage: function (message) {
33                            // Silent stub - prevent crash but don't break functionality
34                            console.debug('[Instagram Guard] Intercepted message to', handler, message);
35                        }
36                    };
37                }
38            });
39        }
40    } catch (e) {
41        console.error('[Instagram Guard] Failed to initialize:', e);
42    }
43})();