Mark Watched YouTube Videos

Add an indicator for watched videos on YouTube. Use GM menus to display history statistics, backup history, and restore/merge history.

These are versions of this script where the code was updated. Show all versions.

  • v1.3.59 2023-11-14

    Fix manual toggle watched marker due to site changes
  • v1.3.58 2023-01-23

    Fixed marker no longer work on video items shown in channel/user search page, due to site changes
  • v1.3.57 2022-11-13

    Fine tune marking of rounded-cornered video list item
  • v1.3.56 2022-11-03

    Added history data size display to statistics. Update for rounded-cornered video list items.
  • v1.3.52 2022-10-28

    Added support to mark video items in the new user/channel "SHORTS" tab
  • v1.3.51 2022-07-26

    Bugfixed a typo in the code which caused videos on "load more" list are nor marked.
  • v1.3.50 2022-07-03

    Bugfix for previous update
  • v1.3.49 2022-07-03

    Update to support older browsers which don't yet support JavaScript optional chaining feature
  • v1.3.48 2022-06-28

    Update due to site changes: markers failed to be applied; broken marker toggling
  • v1.3.47 2021-11-25

    Fixed video items on Recommended page (i.e. home page) failed no longer marked due to site changes
  • v1.3.46 2021-11-02

    Added support for short videos (whose URL uses "shorts" instead of "watch").
  • v1.3.45 2021-06-01

    Increased reliability of video marking on page scroll.
  • v1.3.44 2021-05-28

    Fixed video items added when scrolling page were not reliably marked.
  • v1.3.43 2021-02-03 Fixed "Mix" video items on sidebar of video page didn't get marked due to site changes
  • v1.3.42 2020-09-16 Fixed playlist video entries failed to be marked on search result page
  • v1.3.41 2020-08-31 Adjusted timing of page processing due to site functionality getting slower.
  • v1.3.40 2020-08-15 Fixed broken video markers on main search result page due to site changes
  • v1.3.39 2020-07-23 Added marker outline to surround the video thumbnail and text. For spotting items where the text part is not yet visible in the viewport.
  • v1.3.38 2020-07-20 Fixed failed marking of video list items on channel page's search result due to site changes
  • v1.3.37 2020-06-23 Fixed failed video marking when loading subsequent video list items due to site changes
  • v1.3.36 2020-05-15 Fixed history data merging process replaced the data instead
  • v1.3.35 2020-01-24 Fixed number of history data entries calculation in statistics display. When merging data, data will only be added/updated if not yet exist or if it's older.
  • v1.3.33 2020-01-20 Added ability to merge data and make replace data as optional. Fixed unsynced data index if viewing the same video again. Cosmetic fix.
  • v1.2.30 2019-11-18 Fixed markings of grouped videos on video search result page
  • v1.2.29 2019-11-18 Added support for importing YouTube's own history data JSON format
  • v1.1.28 2019-11-18 Fixed history restore file selector dialog fix for Safari. Included markings of video list on Watch History page. Update markings after restoring history data. Added support for restoring history data from list of URLs.
  • v1.1.24 2019-11-17 Fixed remnants of destructive bug from earlier version
  • v1.1.23 2019-11-16 Bugfix for last update
  • v1.1.22 2019-11-16 Fix for last update: Added GM menus for displaying history statistics, backup history, and restore history. Update for faster history lookup. Changed max history entry age to 5 years.
  • v1.1.21 2019-11-16 Temporary revert
  • v1.1.20 2019-11-16 Added GM menus for displaying history statistics, backup history, and restore history. Update for faster history lookup. Changed max history entry age to 5 years.
  • v1.0.19 2019-11-15 Update for YouTube changes on the new home page video list
  • v1.0.18 2019-09-15 Fixed partially broken marker highlight on old YouTube layout
  • v1.0.17 2019-09-13 Added support for YouTube dark theme. Use dark green highlight when dark theme is used.
  • v1.0.16 2019-04-14 Fixed search result video items did not immediately get marked.
  • v1.0.15 2019-02-05 Fixed broken highlighting due to YouTube site changes. Increased MaxWatchedVideoAge to one year.
  • v1.0.12 2018-09-02 Fixed video items were not marked when they're loaded on page continuation or "show more" button. Changed default maxWatchedVideoAge to 6 months.
  • v1.0.11 2018-04-05 Made the mouse button for toggling the marker configurable, where by default is configured for both ALT+LeftClick or ALT+RightClick.
  • v1.0.10 2018-03-30 Fix broken markers due to yet another YouTube internal changes (sigh...)
  • v1.0.9 2018-03-13 Added workaround for YouTube changes. Please adjust delay configurations in the script.
  • v1.0.8 2018-02-15 Applied workaround to highlight video items listed on user/channel search
  • v1.0.7 2018-02-15 Fatal bug on previous update (sorry)
  • v1.0.6 2018-02-15 Fixed marker highlights don't show on channel/user video search (new YouTube layout only)
  • v1.0.5 2018-01-25 Uses new method to avoid performance loss (new YouTube layout only)
  • v1.0.4 2017-11-27 Added ALT+Click on video list item for manually toggling the watched marker (since previous update). Fix markers for sidebar video list on video page.
  • v1.0.3 2017-11-23 Update for new YouTube layout. Increased default maxWatchedVideoAge to 60 days.
  • v1.0.1 2017-06-02