As you write and edit your posts and pages on WordPress.com, the changes you make are automatically saved every few seconds. In the Publish Module at the top left of the editor, you’ll see when the entry was last saved and can click Save to force the editor to save.
Autosaves are automatically enabled for all posts and pages. The feature can’t be turned off. Each autosaved copy of the post is saved, and you can browse and restore prior versions by clicking on Revisions.
Autosave on Published Content
If you are editing a post or page that has already been published, autosave continues to work but will not overwrite the published content. The changes will not be displayed on the blog until you click the Update Post/Page button in the Publish module. You can find the last autosave, if there is one, and other post revisions in the Post Revisions Module.
Editing a Post/Page with an Autosave
If you go offline while editing or you accidentally navigate away from a post/page while drafting, WordPress.com will save your post to your web browser’s local storage, and you’ll see a note when you return to the editor:
Click Close to return to the draft as-is, or Restore to restore the most recent autosave. You can also browse the revisions at any time to restore an earlier version of your content.