Hi everyone, I’m encountering a critical reliability issue with message passing in my Safari Web Extension on iOS 18.4.1 and iOS 18.5. In my extension, I’m using the standard messaging API. The background script sends a message to the content script using browser.tabs.sendMessage(...), and the content script registers a listener via: browser.runtime.onMessage.addListener(handler); This setup has been working reliably in all prior versions of iOS. However, after updating to iOS 18.4.1 and 18.5, I’ve noticed the following behavior: ✅ The content script is successfully injected, and onMessage.addListener is registered (I see logging confirming this). ✅ The background script sends the message using the correct tabId (also confirmed via logs). ❌ The content script’s onMessage listener is not consistently triggered. ⚠️ This issue is intermittent, sometimes the message is received, sometimes it is silently dropped. ❌ No exceptions or errors are thrown in either script, the message appears to be sent, but not picked up from the content script message listener.

I'm converting a Chrome Extension to a Safari Web Extension, I found it's not easy to get favicon of current tab/url natively. The tab object in Safari doesn't have favIconUrl. { 	"id": 121, 	"index": 6, 	"active": true, 	"width": 1324, 	"audible": false, 	"url": "https://github.com/", 	"mutedInfo": { 		"muted": false 	}, 	"windowId": 2, 	"title": "GitHub", 	"incognito": false, 	"pinned": false, 	"height": 935, 	"highlighted": true, 	"status": "complete" } 		 2. I didn't find Safari has similar thing like chrome://favicon 3. I found Safari's favicon caches in ~/Library/Safari/Favicon Cache/favicons but have no idea how to use them in Safari Web Extension.

I have noticed that storage.local.get API works differently in Safari 18 compare to other browsers and Safari 17. browser.storage.local.set({abc: 123}) browser.storage.local.get(console.log) // {abc: 123} browser.storage.local.get({abc: null}, console.log) // expect {abc: 123} but got undefined instead. According to MDN, storage.local.get should work with an object with object names as keys and the default value as value. According to Safari 18 Release notes, this may be related to a fix: 'Fixed getting an empty key from storage. (99440265) (FB11427769)'.

We used declarativeNetRequest.getMatchedRules() to retrieve the blocked URLs. While we do receive a list, we noticed that the URLs captured do not always reflect the ones the content blocker is actively blocking at that moment. However, upon reloading the same page, the correct URLs appear. Screenshots are attached for your reference. First load: After reload:

Since iPadOS 18.x WKWebView seems to have a bug within its Fullscreen API (which can be enabled via WKPreferences.isElementFullscreenEnabled). This bug has the effect that websites trying to make an element (for example a video player) fullscreen fail to do so. This does not always happen, most of the time the fullscreen mode does work fine, but sometimes (far too often to be ignored) it does not. If an instance of WKWebView shows this issue, it can not be "fixed" by reloading the page or loading other pages, this issue exists in this instance forever. My App is a web browser App so I can create and remove WKWebView instance easily (by opening or closing Tabs). And there are times where I never see this bug, and times where ever other tab shows this bug. It's totally unreliable. The App does not show any issues at all when running under iPadOS 17 or older. The issue is only present under iPadOS 18.x. After some testing I've found out that when the bug has affected an instance of WKWebView, the JavaScript call element.requestFullscreen() will work if the element is a video element, but does no longer work if it is another element (like a DIV). If an instance of WKWebView is not affected by this bug, element.requestFullscreen() will work for all HTML elements. Does anyone has experienced this bug as well? And maybe found a workaround? Or maybe found a pattern which helps to find out what exactly is triggering this bug?

Hello. Environment Safari version 18.1 (22B81). Problem In my Safari Web Extension i need to determine the url of the active tab. I do it this way: const onError = (error) => { console.error(error); }; const getFrameUrl = async (frames) => { console.info(frames) }; const getAllFrames = (frames) => { browser.webNavigation.getAllFrames({ tabId: frames[0].id }).then(getFrameUrl, onError); }; browser.tabs.onUpdated.addListener(() => { browser.tabs.query({ currentWindow: true, active: true }).then(getAllFrames, onError); }); The problem is that if the tab url is a link in the blob protocol, then the result function browser.webNavigation.getAllFrames({ tabId: tabs[0].id }) is as follows: {frameId: 0, parentFrameId: -1, url: "", errorOccurred: false} In Safari version 17 the correct URL value was returned: {frameId: 0, parentFrameId: -1, url: "blob://<some id>", errorOccurred: false} How can I fix the problem? Environment Safari version 18.1 (22B81).

It's being a very long time that I discovery that in some web pages, that use function requestAnimationFrame will cause a lot of cpu, but very little in Chrome. I have already submitted this bug nearly two years ago without printout requestAnimationFrame, no one replied. I submitted again and mention requestAnimationFrame recently, hope there will be some response. If anyone interested in this issue and know some tech in javascript please help. You can enter https://www.baidu.com/ and click one of the topic in all the 百度热搜 which have 弹幕滚动(using requestAnimationFrame, and cause a lot of cpu usage) on right.

I'm developing an application that needs smooth framerates within a wkwebview that interacts with native code. However, requestAnimationFrame by default is still throttled to 60hz even if all my target devices (the iPad Pro for example) have supported 120hz for a long time already. I noticed that the latest Safari in 18.3 beta supports unlocked framerates, but that's only under Safari feature flags. To my knowledge, these flags do not apply to WKWebView. Is there a way to enable unlocked framerate in WKWebView via requestAnimationFrame? (Calling JS at a faster rate from the native code side will not work, almost definitely, since WKWebView will still render at its own rate.) This is an experimental application for internal use and I'm okay if there are temporary beta solutions available.

Hello, I am developing Safari Content Blocker extension and discovered that it frequently fails to load with large amount of rules. Currently I have over 45k and most of the time when I reload the extension on iOS 18 (iPhone 12) it ends with error: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.SafariServices.ContentBlockerLoader" UserInfo={NSDebugDescription=connection to service named com.apple.SafariServices.ContentBlockerLoader} #0 And the simpler message is just: Couldn’t communicate with a helper application. From what I managed to find (for example here - https://developer.apple.com/forums/thread/756931) the limit for blocking rules should be 150k items. It was previously 50k but got increased years ago. Is there anything special I need to do to get the extension to work reliably with say 100k items? I am usng the JSON format from the docs: { "trigger": { ... }, "action": { ... } }, { "trigger": { ... }, "action": { ... } } ] My trigger is url-filter and the action is type: block I was thinking about providing multiple JSON files in attachments property of NSExtensionItem but apparently that is not supported. Thanks for help!

I have a Safari App Extension which allows users to switch between last open tabs with a shortcut option+tab in the same way it's possible to switch between last open apps with command+tab. Here is how i do it: I inject a content script on all websites which has the only thing – key listener for option+tab presses. When a user presses option+tab, that keyboard listener detects it and sends a message to the Safari Handler. Then Safari Handler sends a message to the containing app and it shows a panel with last open tabs. This approach has a problem: it shows a message to a user in settings: "Can read sensitive info from web pages, including passwords..." Which is bad, because in reality i don't read passwords. If i remove SFSafariContentScript key in the Safari App Extension target's Info.plist, then this message about reading sensitive data disappears, but then i loose the ability to open the tabs panel. How can I open my app window with a shortcut without frightening a user? It's possible to listen to global key presses, but that would require a user to grant the app permissions of Accessibility (Privacy & Security) in macOS system settings, which also sounds shady. I know an app which does not require an Accessibility permission: https://apps.apple.com/ua/app/tabback-lite/id6469582909 and at the same time it does not tell a user about reading sensitive data in the extension settings. Here is my app: https://apps.apple.com/ua/app/tab-finder/id6741719894 It's open-source: https://github.com/kopyl/safari-tab-switcher

I’m encountering an issue with a Safari extension bundled with our main application (F-Secure). The extension is not appearing consistently in Safari settings on a customer’s iPad running iOS 18.3. Below are the details of the issue: Issue Description The Safari extension is bundled with the main app (F-Secure). After installing the app, the extension should automatically appear in Settings > Safari > Extensions, where the user can enable it. On the customer’s iPad, the extension is missing from the Safari settings. It briefly appeared once but then disappeared again.

Hello, We’ve been using the CesiumJS WebGL library for several years, both on our website and within embedded WebViews in our iOS application. Since upgrading to iOS versions 18.2 and 18.3, we’ve started receiving numerous user complaints regarding application crashes on various iPad and iPhone models when loading CesiumJS. The crashes occur as soon as the 3D view initializes, and the error consistently reported is: "WebGL context lost" This issue appears to be a WebGL-related crash potentially triggered by GPU memory handling or allocation limits. However, we are not detecting any abnormal memory consumption prior to the crash, and the same setup works perfect on older iOS versions and on all Android devices and versions. Steps to Reproduce: Open: https://www.flightradar24.com/30.47,-94.84/8 Click on any aircraft icon on the map. In the aircraft details panel at the bottom, click on the “3D view” tab. On iOS 18.2 or 18.3, the page will crash shortly after initializing CesiumJS WebGL. Affected Devices: This issue is occurring across a wide range of devices, including: iPad 9th Generation iPad Pro (11-inch, 2nd Gen) iPhone SE (2020 and 2022) iPhone 11, 11 Pro iPhone XR iPhone Mini All of the above are running iOS 18.2 or 18.3. The problem does not occur on Android or previous iOS versions. Request: Has anyone else encountered similar issues with WebGL context loss after upgrading to iOS 18.2 or 18.3? Are there any known changes in memory limits or WebGL behavior in these recent iOS updates? We’d appreciate any insight or suggestions on workarounds or potential fixes. Thank you!

We’re encountering an issue when trying to add non-standard headers to outgoing requests using Declarative Net Request (DNR) rules in our Safari Web Extension. Tested on macOS 15.4 with Safari 18.4. Specifically, when attempting to add a custom header such as "X-Custom-Header" using a DNR rule, the header does not appear in the request. We are able to add standard headers like "Authorization" and "Cookie" to the request successfully using the same method. This behavior suggests that Safari may be filtering or blocking non-standard headers when set via DNR rules, unlike other browsers. In Chrome and Firefox, the same rule adds the "X-Custom-Header" header without any issue. We are looking for assistance in fixing these issues and having our Safari Extension function the same as it does in Firefox and Chrome.

Can someone please help me: I do not have the brain space (85yo) to figure out an Apple Script or Java Script app to do this simple task. I have spent a few hours each day, over several days, and have made zero progress on such an apparently simple task. I wish to create an Automator App for the macOS Safari browser that will schedule (via a Calendar Event) the download of the 48hr data behind the hourly Fuel Mix Plot Data from the AEMO Web Site, every Monday, Wednesday, Friday and Sunday. Here is the link to the AEMO web site: AEMO, Energy Systems, Electricity, National Electricity Market (NEM), Data (NEM),Data Dashboard https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/data-nem/data-dashboard-nem The 48 hour hourly Fuel Mix data is found by selecting the "Fuel Mix" button (which by default will display the NEM Current Trend). The 48 hour trend is displayed by tapping on the small "Current" pulldown menu, and selecting "48 hrs". The 48hr Data is down loaded by selecting the small circular button just to the right of the pulldown menu. a) AEMO Web Site: https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/data-nem/data-dashboard-nem b) Main Menu, and underlying html, c) Fuel Mix menu, Pulldown list, DownLoad button, and underlying html, I am familiar with C++ and have built Xcode Apps, and used Excel Macros extensively in the past. Thank you. Robert.

Does webkit have a way to display a smart banner for a home screen web app similar to how a smart banner can be displayed for native apps? I recently noticed (10/23) that Twitter showed a smart banner encouraging Home Screen web app on my Mac running Sonoma. How is this done?

Hi! We are having a hard time with the universal link, help is appreciated! Thanks in advance! The universal link doesn't work after installation for some time. A user has to wait for from 5 to a couple of hours after the app is installed on the device. This has also affected App reviewers since we need the universal link to work for successful login. Each submission will receive a rejection of we cannot login and it will be approved until we kindly ask them to try again. I believe the JSON is delivered to devices by Apple's CDN system and the fact that it works on most devices most of the time should imply that we have a valid apple-app-site-association setup. So I am really confused about the wait time, which is giving us trouble with app review and a bad user experience

We are using declarativeNetRequest.getMatchedRules() to get the matched rules' URLs. When user switches website in the same tab, it returns URLs which were blocked in the previous website also, within past 5 minutes. Is it possible to fetch getMatchedRules() only for current webpage in the same tab?

I have noticed that tabs.onRemoved works differently in Safari 18 comparing to other browsers and Safari 17. Open a tab e.g. apple.com Take note of the active tab id using this code: browser.tabs.query({currentWindow: true, active: true}, (x) => console.log(x[0].id)) Add a listener on onRemoved: browser.tabs.onRemoved.addListener(console.log) on the active tab, navigate to e.g. https://developer.mozilla.org Take note of the active tab id again (using the same tabs.query). Expect: there should be no console.log of onRemoved. the active tab id stays the same. Actual: there is a console.log of onRemoved. the active tab id is changed. Please help. If this is a bug introduced in Safari 18, it would break a lot of JS Web extensions.

Hi. I've noticed on both iOS 17 and iPadOS 16 that when an user opens a website in a WKWebview (e.g from Gmail), then requests it to be opened in the external Safari app (through the "compass" icon), their localStorage data is not transferred to the Safari tab. This behaviour breaks web experiences that rely on data being locally stored, e.g auth tokens or user identification data. It effectively stops users from being able to use some websites outside of an in-app context. I am aware of Webkit's tracking prevention mechanisms such as https://webkit.org/tracking-prevention/#partitioned-third-party-localstorage, but I don't think this should apply to this case. Here the user is navigating between two Safari tabs (one internal and one external) on the same domain, exact same URL, by pressing a native Safari webview icon. There is no third-party cross-domain tracking happening. Is this a bug or intended behaviour?

I'm developing an application that utilizes WKWebView to display a webpage. My goal is to improve the performance and loading speed of this webpage by intercepting specific API calls and providing pre-stored JSON responses directly from within the app, ensuring the webpage renders instantaneously. The challenge I am encountering is the inability to intercept HTTPS URL schemes directly from WKWebView. Any insights or solutions from the community on how to effectively manage and overwrite these particular network requests would be greatly appreciated.