Load Background Tabs Lazily

Allow only a specific number of new background tabs to load at one time.

★ Please read the 'Issues/Limitations' section below before installing, especially the issues regarding Manifest V3. ★ Load Background Tabs Lazily is a port of a Firefox extension that duplicates some of the behavior of an older Firefox extension, Load Tabs Progressively. Load Background Tabs Lazily places newly created background tabs in a line and allows only a specific number to load, while blocking the rest. A tab is removed from the line once it has finished loading. The first blocked tab in the line is then allowed to load. This extension was designed for users with slow internet connections that routinely open multiple background tabs at the same time. It also helps users that open many background tabs at once by not overwhelming their browser or CPU. Only background tabs with http or https URLs are added to the line. Middle click (or Ctrl click) a link, bookmark, or bookmark folder to create background tabs. Various commands or settings for this extension can be accessed in its Options page or toolbar button popup. The toolbar button can be pinned by clicking the 'Extensions' button that looks like a puzzle piece on the toolbar. 🔹 Issues/Limitations ▸ There is an issue in Manifest V3 where a service worker may stop almost immediately after a computer awakens from sleep. This problem affects this extension when using Chrome (and Edge) in Windows. The service worker should 'probably' resume without stopping if using Chrome in Linux. It is best if all tabs in the line are loaded before putting a computer to sleep with Chrome in Windows until this issue is fixed. While not always the case, assume that this extension will restart with a clean slate after coming out of sleep mode. ▸ This extension lost the ability to block URLs in real time after updating to Manifest V3. It can no longer use its own internal logic to decide on whether a new tab should be blocked. It now uses rule based blocking to prevent tabs from loading. Previously, if a tab was active (focused), it wouldn't be blocked. Now, all new tabs created with http(s) URLs are blocked by default through a predefined rule (except tabs with whitelisted URLs). This includes active tabs. After a new active tab is blocked, a rule will be updated to place the new tab in 'allow' mode and then the tab will get reloaded. One drawback to blocking and reloading a new active tab is that form data and page position will be lost if the tab is a restored or duplicated tab. It may have been restored from a previous session (Settings - On Startup - Continue where you left off) or by performing a 'Reopen closed tab/group/window'. In these cases, there are a couple ways to prevent data loss. The option in this extension 'Create a session based block rule on browser startup' will prevent active tabs created on browser startup from being blocked. The rule will not take effect quickly enough to apply to tabs created immediately on browser startup. This option is selected by default, but it may need to be changed depending on which browser settings a user has selected (Settings - On startup). There are also commands to enable or disable manual queuing or turn the extension 'Off'. There is no block rule in place for new tabs when this extension has manual queuing enabled or when it is 'Off', so tabs may safely be restored or duplicated. There is another case to be aware of when manually restoring a window (not automatically restoring on browser startup). Depending on how many tabs are in the window (not a large amount) and the position of the active tab (closer to the first tab than the last), the first tab in the window may immediately get loaded faster than a rule can get updated to 'allow' it. It will then get blocked and reloaded by this extension unless manual queuing is enabled or it is 'Off'. ▸ Many Chrome tabs API functions don't work on tabs in a saved tab group in Chrome 124, like 'chrome.tabs.reload'. In other words, this extension won't be able to load tabs in a saved tab group until this is fixed in a later version. ▸ YouTube pages usually can't be blocked ( https://issues.chromium.org/issues/40747297 ). There may possibly be a few other sites that should be blockable, but aren't. There are also restricted sites that aren't allowed to be blocked, like 'chromewebstore.google.com'. ▸ Options are available in this extension to add discarded and unloaded tabs to the line. The chrome.tabs.reload function will be used on these tabs to load an up-to-date version of a web page. Form data and page position will be lost. If a discarded or unloaded tab that is not in the line is selected or activated, often a cached version of the web page will load and form data and page position will be restored. ▸ When creating multiple tabs at once, some extensions will create them all as active tabs. Focus will end up on the last tab created, usually the rightmost tab. Enabling the option 'Add new tabs to the line that are created as active tabs.' is necessary to add these tabs to the line. ▸ If the first tab created in a window is unloaded (restored), it is ignored by this extension. It won't be added to the line or discarded (if the option is selected). ▸ There is a brief moment when pressing Esc on a tab right as it starts loading may not generate an error event. If this happens to a tab in the line, it will need to be removed manually. ▸ When opening 100's of tabs, it is possible that they may not all be viewable or easily accessed in the tab bar. Enabling 'Tab Scrolling' and 'Tab Scrolling Buttons' in the Experiments page ( chrome://flags ) may be helpful. 🔹 Permissions used (nonoptional): ▸ "declarativeNetRequest": allows an extension to block URLs from loading using predefined rules without requiring broad host permissions (Read and change all your data on websites). ▸ "webNavigation": allows an extension to view various stages of a web navigation such as when a tab commits to loading a URL or completes loading.** ▸ "tabs": allows access to every tabs URL.** ▸ "storage": allows an extension to locally store data, like modified options. ▸ "contextMenus": allows an extension to add menu items to context menus. ** The "tabs" and "webNavigation" permissions allow an extension to view URLs of currently opened or loading tabs. When installing this extension, a prompt will warn that it can 'Read your browsing history'. However, this extension cannot truly view a users history. It does not have the 'history' permission***. It can only view URLs of tabs currently opened when it is enabled. *** A quick method of viewing an installed extensions permissions is to open the chrome://extensions-internals page and search for the extension using its name. 🔹 Version history: =============== Version 4.3 (4/24/2024): updated extension to manifest v3. added option to make new manifest v3 block rule dynamic based (rule lasts across browser restarts) or session based (rule cleared when the browser shuts down). added 'service worker' section to the options page. added option to delay loading tabs when downloads are in progress. added option to delay loading tabs when images are loading in the browser. added an idle button badge. added ability to change button badge text colors. =============== Version 4.2: fixed an issue with the 'move new background tabs to the end...' option. =============== Version 4.1: fixed an issue that could cause new tabs to not get added to the line. updated the date this extension will switch to manifest v3. =============== Version 4.0: minor code improvement and added advanced option 'display logs' that is for debugging purposes only. =============== Version 3.9: added option to not add non-loading (discarded, unloaded, and completed) tabs to the line if they are whitelisted. added advanced option 'completion delay overrides' that allows the 'completion delay' timer to be different on specific sites.. =============== ... Older version history is in this extensions Options page (Options - About).