如何修复Python Selenium脚本中的innerHTML赋值错误

问题背景 #

Python+Selenium开发的Gmail发送脚本此前运行正常，Gmail更新后出现JavaScript错误，无法将HTML模板内容插入邮件正文区域。

错误信息 #

selenium.common.exceptions.JavascriptException: Message: javascript error: Failed to set the 'innerHTML' property on 'Element': This document requires 'TrustedHTML' assignment.
  (Session info: chrome=122.0.6261.111)

完整错误栈：

Traceback (most recent call last):
  File "C:\Users\Administrator\Desktop\New folder\gmailsender.py", line 101, in <module>
    sb.driver.execute_script(f'document.querySelector(\'div[role=&quot;textbox&quot;]\').innerHTML = `{body_content}`;')
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python312\Lib\site-packages\selenium\webdriver\remote\webdriver.py", line 407, in execute_script
    return self.execute(command, {"script": script, "args": converted_args})["value"]
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python312\Lib\site-packages\selenium\webdriver\remote\webdriver.py", line 347, in execute
    self.error_handler.check_response(response)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python312\Lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 229, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.JavascriptException: Message: javascript error: Failed to set the 'innerHTML' property on 'Element': This document requires 'TrustedHTML' assignment.
  (Session info: chrome=122.0.6261.111)
Stacktrace:
        GetHandleVerifier [0x00007FF72267AD22+56930]
        (No symbol) [0x00007FF7225EF622]
        (No symbol) [0x00007FF7224A42E5]
        (No symbol) [0x00007FF7224A9261]
        (No symbol) [0x00007FF7224AB9FD]
        (No symbol) [0x00007FF722528E57]
        (No symbol) [0x00007FF72250BC9A]
        (No symbol) [0x00007FF7225281E2]
        (No symbol) [0x00007FF72250BA43]
        (No symbol) [0x00007FF7224DD438]
        (No symbol) [0x00007FF7224DE4D1]
        GetHandleVerifier [0x00007FF7229F6AAD+3709933]
        GetHandleVerifier [0x00007FF722A4FFED+4075821]
        GetHandleVerifier [0x00007FF722A4817F+4043455]
        GetHandleVerifier [0x00007FF722719756+706710]
        (No symbol) [0x00007FF7225FB8FF]
        (No symbol) [0x00007FF7225F6AE4]
        (No symbol) [0x00007FF7225F6C3C]
        (No symbol) [0x00007FF7225E68F4]
        BaseThreadInitThunk [0x00007FF8B4BE4ED0+16]
        RtlUserThreadStart [0x00007FF8B5ACE39B+43]

报错代码行：
sb.driver.execute_script(f'document.querySelector(\'div[role="textbox"]\').innerHTML = {body_content};')

问题原因 #

Gmail更新后启用了Trusted Types安全机制，该机制会阻止直接将字符串赋值给innerHTML等风险属性，要求必须使用经过信任的TrustedHTML类型内容，防止XSS攻击。

解决方案 #

方法1：使用Trusted Types API合法赋值（推荐） #

修改JavaScript执行代码，通过创建信任策略将HTML内容转换为TrustedHTML后赋值：

# 替换原报错代码行
sb.driver.execute_script("""
// 创建信任策略
const policy = trustedTypes.createPolicy('gmail-html-policy', {
  createHTML: (html) => html
});
// 获取邮件正文元素并赋值
const emailBody = document.querySelector('div[role="textbox"]');
emailBody.innerHTML = policy.createHTML(arguments[0]);
""", body_content)

方法2：模拟剪贴板粘贴HTML #

通过模拟用户粘贴操作插入HTML内容，绕过Trusted Types限制：

import pyperclip
from selenium.webdriver.common.by import By

# 将HTML内容写入剪贴板
pyperclip.copy(body_content)

# 定位邮件正文区域并触发粘贴
email_body = sb.driver.find_element(By.CSS_SELECTOR, 'div[role="textbox"]')
email_body.click()
sb.driver.execute_script("document.execCommand('paste');")

注意：需确保Chrome启动时添加剪贴板权限参数：

from selenium.webdriver.chrome.options import Options
chrome_options = Options()
chrome_options.add_argument("--enable-clipboard-read")
chrome_options.add_argument("--enable-clipboard-write")

方法3：禁用Trusted Types（临时测试用，不推荐） #

通过Chrome启动参数关闭Trusted Types机制，仅适合本地测试：

from selenium.webdriver.chrome.options import Options

chrome_options = Options()
chrome_options.add_argument("--disable-features=TrustedTypes")
# 初始化driver时传入options
driver = webdriver.Chrome(options=chrome_options)

内容的提问来源于stack exchange，提问作者hummorrrflov