greasemonkey.md

It's an extension for many browsers (major ones and not) that enables a user to write some JS for small automation or improvements on various websites. It reads js files that a user created and executes them based on the conditions coded in.

A script contains a header declaring the environment to run in, and a code immediately follows.

Simplest code might be directly operating on the DOM-tree with document variable. So e.g.: document.head.foo.bar.value = 'mytext'. IRL DOM-tree is often complicated, so a better way me be to use standard js searching functions. For example:

// ==UserScript==
// @name     pre filling some text
// @version  1
// @match    https://example.com/search*
// ==/UserScript==
my_txtbox = document.getElementById('some_text_box');
my_txtbox.value = 'my pre-filled value';

• @match is a URL for the script to run in, supports globbing with *.
• @require https://foo.bar… using a GreaseMonkey script from that URL. Useful to avoid coding stuff that already exists in libraries, such as waitForKeyElements() that waits for an element to appear then executes a lambda on it.

Debugging

In Firefox pressing F12 will get you a console at the bottom-right, and then upon reloading the page where script is supposed to run you shall see any errors or console.log() output that may be coming from the script.

Qutebrowser

Scripts have to be put under ~/.config/qutebrowser/greasemonkey/ directory. To make QB reload them execute :greasemonkey-reload.