Replace web fonts with browser's default fonts
// ==UserScript==
// @name Default fonts
// @version 1.1
// @description Replace web fonts with browser's default fonts
// @author KenHV
// @namespace https://kenhv.com
// @supportURL https://kenhv.com
// @homepageURL https://kenhv.com
// @match *://*/*
// @grant none
// @run-at document-start
// ==/UserScript==
(function () {
"use strict";
// Cache to keep track of processed rules and stylesheets
const processedRules = new WeakSet();
const processedStyleSheets = new WeakSet();
function fontReplace() {
Array.from(document.styleSheets).forEach((styleSheet) => {
if (processedStyleSheets.has(styleSheet)) {
return;
}
let rules;
try {
rules = Array.from(styleSheet.cssRules);
} catch (err) {
return;
}
rules.forEach((rule) => {
if (rule instanceof CSSStyleRule && !processedRules.has(rule)) {
if (rule.style.fontFamily.includes("sans")) {
rule.style.fontFamily = "sans-serif";
processedRules.add(rule);
return;
}
if (rule.style.fontFamily.includes("serif")) {
rule.style.fontFamily = "serif";
processedRules.add(rule);
return;
}
if (rule.style.fontFamily.includes("mono")) {
rule.style.fontFamily = "monospace";
processedRules.add(rule);
return;
}
processedRules.add(rule);
}
});
processedStyleSheets.add(styleSheet);
});
}
fontReplace();
// Use MutationObserver to react to changes in the DOM
const observer = new MutationObserver(() => {
fontReplace();
});
observer.observe(document.documentElement, {
childList: true,
subtree: true,
});
})();