All editable pages on Bulbapedia have an associated page history which consists of the old versions of the wikicode as well as a record of the date and time (in UTC) of every edit, the username of the user who wrote it and their edit summary. Access the page history by clicking the "history" tab at the top of the page (this works slightly differently on mobile). This may also be referred to as the revision history or edit history.
On a history page:
- All past changes to the page in question are listed in reverse-chronological order.
- To view a specific revision, click a date.
- To compare an old revision with the current revision, go to the old revision, click cur.
- To compare a revision with its predecessor, click prev.
- To compare two specific revisions, click the left-column radio button of the older revision and the right-column radio button of the newer revision, and then click the "Compare selected revisions" button.
- To undo (revert) your own or someone else's edit, click the "undo" link.
Below is a detailed example of a page history using the default skin (Monobook):
The edits are listed in chronological order from newest to oldest, and are displayed with each edit being their own row in the list, with each row taking up one line of text. Each entry in the edit history will show the time and date that the edit was applied, the username of the contributor who saved the edit, the total size of the resulting page text (in bytes), the net size difference (in bytes) that the changes made from the edit resulted on the page[note 1], the edit summary that was added by the contributor, as well as other technical and diagnostic information.
Let's look at some of the functions of this page:
- The "History" tab is highlighted and "Revision history of" is added to the page name. Notice that you can't make wikilinks to this extended page name – to make a link to the history page, copy the URL from the browser address bar when viewing the history page, and paste it between single square brackets (external link format) to make the link.
- The "To date:" field allows a quick jump when the page has many revisions. After entering a date, click the "Show revisions" button below.
- The "Tag filter:" restricts the display to show only those edits that have been tagged by an edit filter. For example, "references removed" may be entered here. After entering a tag name, click the "Show revisions" button below.
- The "Revision deleted only" checkbox is only shown to administrators and others with the
- These links take you to the most recent edits (latest), oldest edits (earliest) or the next or previous page of edits (newer n / older n). Note that the black text in brackets will become links, when applicable.
- The blue numbers list the number of edits displayed on a page - 20, 50, 100, 250 or 500. A higher number increases the length of a page, but reduces the number of pages. The number you select replaces n in the links to the previous or next pages e.g. (newer 100 / older 100). Manipulating the
limitterm in the URL lets you set this number as high as 5000.
- (cur) takes you to a diff page, showing the difference between that edit and the current revision. The current revision appears below the changes, so you can see how the page is now rendered.
- (prev) takes you to a diff page showing the changes between that edit and the previous revision. The most recent revision (the one on the same line as the "prev" you clicked on) appears below the changes, so you can see how the page was rendered.
- The two columns of radio buttons can be used to select any two revisions on the page. The current selection is marked by a special background. The two most recent revisions are selected by default when you first view the history. Let's say you want to compare the revisions corresponding to numbers 9 & 10 on the image. First, click the left radio button next to number 10. The right column of buttons will then fill as far as number 10. Then click the right button next to number 9. Finally, click Compare selected revisions. This takes you to a diff page showing the changes between the two revisions. The most recent revision (in this case number 9) appears below the changes, so you can see how the page was rendered.
- This gives the time and date of the edit. The time is UTC by default on Bulbapedia. Users can choose date format and time zone in their preferences. The date and time contains a link to that revision of the page.
- The username of the contributor appears here.
- m stands for minor edit.
- The size of the page in bytes (roughly corresponding to characters)
- The difference in size between this revision and the previous revision. A green number with a plus sign (+1,864) indicates that the edit added this number of bytes (roughly corresponding to characters) to the page, while a red number with a minus sign (−29) indicates removal.
- This is the edit summary. It is the text the user wrote in the edit summary box (below the edit box).
- This edit summary begins with an arrow link and grey text. This means the user has only edited a section of the page (named in the grey text). This text is automatically added when you edit a section. The arrow links to that section of the current revision of the page, and not the revision where the arrow was clicked. A standard edit summary can be added by the user. This appears in black text.
Not shown in this example: some edits may be automatically tagged by the abuse filter (example:
(Tag: references removed)); any tags applied appear after the edit summary. Tags cannot be added or removed manually, and are intended to help editors identify potential problem edits for examination; they do not prove that an edit is problematic.
It is possible to restore an old revision of a page by following the link to that revision, clicking "edit" and then saving. This should be done with caution, as it means that all changes made to the page since the time of that revision will be undone.
In rare cases, all or part of a page history entry may be shown in grey, struck out by a horizontal line. This indicates that information has been hidden from public view by an administrator.
- This will either be a positive number colored in green if the net difference added more text to the page than removed, a negative number colored in red if the net difference removed more text to the page than added, or zero and colored grey if the net changes did not modify the total size of the page at all)
On the mobile version of Bulbapedia, tap "Last edited" near the bottom of a page see the page history. Logged-in users can also tap the icon at the top of mobile pages. Other parts of this page describe the desktop version of the site. It looks different from the mobile version and has more interface features. Mobile users can switch to the desktop version by tapping "Desktop" at the bottom of any page.
Moved and deleted pages
When a page is moved (renamed), the entire edit history of the article, before and after the move, is shown. The old title becomes a redirect and loses its edit history. To view a history of only moves and no other edits, go to Special:Log/move and input the name of the article in the "target" field. When two pages are merged, typically one becomes a redirect. In this case, the revision history of the redirect is kept.
When a page is deleted, its revision history remains in the database and can be retrieved by an administrator, who can also undelete the page. Administrators can also remove selected revisions from a page history, for example if they contain defamatory text.