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Prevent highlighting

Prevent highlighting on manga sites

当前为 2025-08-09 提交的版本，查看 最新版本。

// ==UserScript==
// @name         Prevent highlighting
// @namespace    http://tampermonkey.net/
// @version      2025-08-09
// @description  Prevent highlighting on manga sites
// @author       You
// @match        https://weebcentral.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=create.t3.gg
// @grant        none
// @license      GNU GPLv3
// ==/UserScript==

(() => {
  let enabled = true;

  const STYLE_ID = 'tm-no-select-style';

  // CSS that blocks selection everywhere except form/editable elements
  const css = `
    html, body, * {
      -webkit-user-select: none !important;
      -moz-user-select: none !important;
      -ms-user-select: none !important;
      user-select: none !important;
    }
    input, textarea, select, [contenteditable=""], [contenteditable="true"] {
      -webkit-user-select: text !important;
      -moz-user-select: text !important;
      -ms-user-select: text !important;
      user-select: text !important;
    }
  `;

  const eventsToBlock = [
    'selectstart',   // text selection start
    'dragstart',     // double-click + drag
    'mousedown',     // some sites use this to trigger selection
    'pointerdown',   // pointer-based selection
    'dblclick'       // double-click selection
  ];

  // Add a style element to a (shadow) root
  function injectStyleInto(root) {
    if (!root || !root.ownerDocument) return;
    const doc = root.ownerDocument;
    // Avoid duplicates per root
    const existing = [...(root.querySelectorAll ? root.querySelectorAll(`#${STYLE_ID}`) : [])].length;
    if (existing) return;

    const style = doc.createElement('style');
    style.id = STYLE_ID;
    style.textContent = css;
    (root.head || root).appendChild(style);
  }

  // Attach event blockers at the root level
  function attachEventBlockers(target) {
    eventsToBlock.forEach(evt => {
      target.addEventListener(evt, onBlocker, { capture: true, passive: false });
    });
  }

  // Permit selection inside form/editable controls
  function isEditable(el) {
    if (!el) return false;
    if (el.closest('input, textarea, select')) return true;
    const ce = el.closest('[contenteditable]');
    return ce && (ce.getAttribute('contenteditable') === '' || ce.getAttribute('contenteditable') === 'true');
  }

  function onBlocker(e) {
    if (!enabled) return;
    if (isEditable(e.target)) return;
    e.stopPropagation();
    e.preventDefault();
  }

  // Process the main document and any existing shadow roots
  function processDocument(doc = document) {
    injectStyleInto(doc);
    attachEventBlockers(doc);

    // Walk the tree to find shadow roots already attached
    const walker = doc.createTreeWalker(doc, NodeFilter.SHOW_ELEMENT);
    let node;
    while ((node = walker.nextNode())) {
      if (node.shadowRoot) {
        processShadowRoot(node.shadowRoot);
      }
    }
  }

  // Handle a shadow root
  function processShadowRoot(sr) {
    injectStyleInto(sr);
    attachEventBlockers(sr);
  }

  // Intercept future shadow roots
  const origAttachShadow = Element.prototype.attachShadow;
  Element.prototype.attachShadow = function(init) {
    const sr = origAttachShadow.call(this, init);
    // Process after creation
    queueMicrotask(() => processShadowRoot(sr));
    return sr;
  };

  // Observe added elements to catch closed-over cases where styles might be removed
  const mo = new MutationObserver(muts => {
    if (!enabled) return;
    for (const m of muts) {
      if (m.type === 'childList') {
        m.addedNodes.forEach(n => {
          // Re-inject style into document if removed
          if (n.nodeType === 1) {
            const el = /** @type {Element} */ (n);
            // If a <style> got removed elsewhere, ensure one exists
            if (!document.getElementById(STYLE_ID)) injectStyleInto(document);
            // Shadow roots on newly added custom elements (if any) get handled by attachShadow hook
          }
        });
      }
    }
  });

  function enable() {
    enabled = true;
    injectStyleInto(document);
    attachEventBlockers(document);
  }

  function disable() {
    enabled = false;
  }

  // Keyboard toggle: Ctrl + Alt + U
  window.addEventListener('keydown', (e) => {
    if (e.ctrlKey && e.altKey && (e.key === 'u' || e.key === 'U')) {
      enabled ? disable() : enable();
      // Optional toast
      try {
        const msg = `No-select: ${enabled ? 'ON' : 'OFF'}`;
        console.log(msg);
      } catch {}
      e.preventDefault();
      e.stopPropagation();
    }
  }, { capture: true });

  // Initialize
  if (document.readyState === 'loading') {
    // document-start, but DOM not ready yet
    processDocument(document);
  } else {
    processDocument(document);
  }
  mo.observe(document.documentElement || document, { childList: true, subtree: true });
})();