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Default fonts

Replace web fonts with browser's default fonts

  1. // ==UserScript==
  2. // @name         Default fonts
  3. // @version      1.1
  4. // @description  Replace web fonts with browser's default fonts
  5. // @author       KenHV
  6. // @namespace    https://kenhv.com
  7. // @supportURL   https://kenhv.com
  8. // @homepageURL  https://kenhv.com
  9. // @match        *://*/*
  10. // @grant        none
  11. // @run-at       document-start
  12. // ==/UserScript==
  13.  
  14. (function () {
  15.   "use strict";
  16.  
  17.   // Cache to keep track of processed rules and stylesheets
  18.   const processedRules = new WeakSet();
  19.   const processedStyleSheets = new WeakSet();
  20.  
  21.   function fontReplace() {
  22.     Array.from(document.styleSheets).forEach((styleSheet) => {
  23.       if (processedStyleSheets.has(styleSheet)) {
  24.         return;
  25.       }
  26.  
  27.       let rules;
  28.       try {
  29.         rules = Array.from(styleSheet.cssRules);
  30.       } catch (err) {
  31.         return;
  32.       }
  33.  
  34.       rules.forEach((rule) => {
  35.         if (rule instanceof CSSStyleRule && !processedRules.has(rule)) {
  36.           if (rule.style.fontFamily.includes("sans")) {
  37.             rule.style.fontFamily = "sans-serif";
  38.             processedRules.add(rule);
  39.             return;
  40.           }
  41.           if (rule.style.fontFamily.includes("serif")) {
  42.             rule.style.fontFamily = "serif";
  43.             processedRules.add(rule);
  44.             return;
  45.           }
  46.           if (rule.style.fontFamily.includes("mono")) {
  47.             rule.style.fontFamily = "monospace";
  48.             processedRules.add(rule);
  49.             return;
  50.           }
  51.           processedRules.add(rule);
  52.         }
  53.       });
  54.  
  55.       processedStyleSheets.add(styleSheet);
  56.     });
  57.   }
  58.  
  59.   fontReplace();
  60.  
  61.   // Use MutationObserver to react to changes in the DOM
  62.   const observer = new MutationObserver(() => {
  63.     fontReplace();
  64.   });
  65.  
  66.   observer.observe(document.documentElement, {
  67.     childList: true,
  68.     subtree: true,
  69.   });
  70. })();