只读克星：前端眼里，没有「read only」文档这回事

readonly-breaker.js

// 粘贴到 chrome devtool console 中执行
// 使用场景 
//    1. 想复制只读文档的内容
//    2. 担心复制内容的行为被公司监听了

function removeAllEvents(event) {
  function removeEvent(el, type) {
    const listeners = (getEventListeners(el)[type] || []);

    el[`on${type}`.toLowerCase()] = null;
    listeners.forEach(({ type, listener, ...opts }) => {
      el.removeEventListener(type, listener);
      el.removeEventListener(type, listener, true);
      el.removeEventListener(type, listener, opts);
    });
  }

  const events = event.split(/\s+/);
  const remove = (el) => events.forEach(e => removeEvent(el, e));

  remove(window);
  remove(document);
  document.querySelectorAll('*').forEach(remove);

  document.querySelectorAll('iframe').forEach(el => {
    try {
      remove(el.contentWindow);
      remove(el.contentDocument);
      el.contentDocument.querySelectorAll('*').forEach(remove);
    } catch (e) {}
  });
}

removeAllEvents('copy keyup keydown keypress select selectstart selectend selectionchange')