Creating Javascript Bookmarklets

Created 24-05-2025, last change 24-05-2025

An interesting option for performing small actions in the browser is to write a Javascript bookmarklet - which are a bookmark that does not open a new URL but contains a small piece of Javascript code that is executed on the currently shown page instead. The most interesting example I’ve seen so far is probably the Printliminator, which allows you to selectively remove stuff from the page before printing it from the browser, and, of course, my ChatGPT bookmarklet. :-) More examples are below. But a bit of the how first.

Creating a bookmarklet is easy: open the inspector / debugger in the browser, develop a bit of Javascript code that does what you want, url-encode that, put javascript: in front of it and then make a bookmark with that URL and you’re done. Still too complicated? Here is my bookmarklet maker that lets you input the name of the bookmark and the Javascript code and then shows a link which you can just drag into your bookmark bar. If you’ve treated yourself to an OpenAI API key you can even just type in a description what it should do and then let ChatGPT create the Javascript code for you.