Silence of the Tabs - Suspending inactive tabs since 2017

This chrome extension helps keeping your PC sane, by suspending inactive tabs, saving memory, CPU cycles and stopping ads and videos from making noise.

Deprecation notice

Since I originally wrote this extension, several changes have happened, that make it obsolete:

1. Chrome has gained some features, that make this extension redundant, as it now limits resource usage of background tabs.

2. Redirecting to data:...-URIs has been disabled for a while for code executed in the webpage context, but somewhere along the line it was also disabled for the chrome.tabs API, which this extension depends on.

Comparison to other software

Alternatives include The Great Suspender and TabMemFree, the latter being the primary motivation for this addon.

The Great Suspender

The Great Suspender uses the chrome-extension:// protocol to store parked tabs. This enables it's advanced features, but

• Loses tabs, when uninstalling the extension
• Breaks synchronization of opened tabs to Chrome on mobile devices

TabMemFree

TabMemFree suspends tabs by redirecting to a webpage, which simply toggles the [Back] button when the tab is focused again (technically history.back()).

This mostly works well, but

• sometimes left me losing tabs after crashes.
• might lose the required webpage at any time, given that the Github repository hasn't been active since 2012.
• might break third-party synchronization services, that don't synchronize the full tab history.

In order to solve the perceived issues (and learn JavaScript along the way) I chose to write an alternative from scratch, storing the suspended tab in a data: url, which also encodes the full URL of the parked tab. Since data-urls are local, no private information is leaked.

• Data URLs can be easily synced, as long as they are not too long (see Limitations).
• Data URLs don't depend on external resources; The extension will work even without access to the internet.

Compared to TamMemFree, this addon adds the subsequent features:

• The extension-icon allows suspending the current tab, or all other tabs in the current window which can be suspended.

Limitations

Because chrome will only synchronize tabs with URLs up to some maximum length, data-URLs must be kept short. This has prevented the inclusion of a webpage-screenshot in the data url.

Known Issues

Currently, no major issues are known.

If you want to report a new bug, check the issue tracker.

Change Log

2018-07-04 (v0.2.2) Quick update with icon.png to conform with new policies of Chrome extension store.

2017-10-02 Bugfix: Suspended tabs didn't use history.back() if only one entry before suspension.

2017-08-15 (v0.2.1)

Developer Notes

• All code is contained in main.js for simplicity.
• Background page, options page, popup page, ... all delegate to main.html and thus main.js, which decide page-content and activity based on the #HashTag.
• The tab-suspension mechanism is handled entirely by main.js/tabs.suspend, allowing simple replacement.
• As of writing, the addon code doesn't depend on any external libraries. It is pure Vanilla JS, except for browser-provided APIs (chrome.tabs, chrome.storage).

Open Ideas

• Screenshots Sadly it seems that there is no viable way to include a screenshot. The html2canvas library allows creating the screenshot, but currently no way for including it into the suspension-page is known. Multiple variations have previously failed:

  1. Blob URIs The data: uri scheme counts as an isolated origin, and therefore has no access to the blobs.
  2. Data URIs Image can be included as <img src='data:...'>, but this results in an extremely long page url for the "suspended tab" data URI, which would break synchrnozation with mobile.
  3. Image injection With appropriate permissions, chrome.tabs.executeScript could insert the data URI image from within the extension. Sadly, no combination of permissions seems to allow content-script access to data URIs.