Bookmarklets are browser bookmarks that run some JavaScript instead of navigating to a website. They can do anything JavaScript can do including change fonts, search for phone numbers, remove all images, change the background color, automatically fill a form, and so much more.
This guide by Hongkiat Lim explains bookmarklets in more detail and lists many of the most popular ones.
More examples
- Here’s one I made. You can drag it into your bookmarks bar: copy markdown link. It puts into the clipboard a markdown link for the current page using the tab’s title as the link title.
- web-automation/bookmarklets, by Marco D’Agostini, is a collection of bookmarklets
- Obsidian Web Clipper Bookmarklet, by Steph Ango, converts websites to markdown and saves them directly to Obsidian
- Jesse’s Bookmarklets Site (last updated in 2004)
Bookmarklet editors
- Bookmarklet Editor, by Marek Gibney, also has a few examples you can see by clicking the question mark on the page
- Bookmarklet Creator with Script Includer by Peter Coles
- Bookmarkify.it by Achilleas Buisman