javascript - 如何让 Puppeteer/Node 脚本按其类读取 <div> ？

Question

有没有办法选择 <div>按其在 Node Puppeteer 网络爬虫中的类？

有一个div在如下所示的网页上:<div class="Body-body-qL80Q">

我希望我的抓取工具能够抓取 div 中的文本。目前，我只是尝试将其写入控制台以检查它是否获取了正确的文本。

我的querySelector怎么了？ ？ (我之前让脚本导航到正确的页面并截取屏幕截图，它做得正确，所以我知道它的其余部分有效。)

const puppeteer = require('puppeteer');
const CREDS = require('./creds');

(async () => {
  const browser = await puppeteer.launch({ headless: true });

  const page = await browser.newPage();

  await page.goto('https://www.squarespace.com/login');

  const USERNAME_SELECTOR = '.username.Input-hxTtdt.ipapEE';
  const PASSWORD_SELECTOR = '.password.Input-hxTtdt.ipapEE';
  const BUTTON_SELECTOR = '.Button-kDSBcD.fATVqu';

  await page.click(USERNAME_SELECTOR);
  await page.keyboard.type(CREDS.username);

  await page.click(PASSWORD_SELECTOR);
  await page.keyboard.type(CREDS.password);

  await Promise.all([
    page.waitForNavigation(),
    page.click(BUTTON_SELECTOR),
  ]);

  await page.goto('https://triangle-oarfish-hk88.squarespace.com/config/analytics#activity-log');

  const textContent = await page.evaluate(() => document.querySelector('Body-body-qL80Q').className);

  console.log(textContent);

  await browser.close();
})();

这是错误:

(node:6116) UnhandledPromiseRejectionWarning: Error: Evaluation failed: TypeError: Cannot read property 'className' of null
(node:6116) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:6116) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

您忘记在 document.querySelector() 中的类选择器 Body-body-qL80Q 之前添加句点 .里面的功能page.evaluate() :

此外，您应该使用 textContent属性而不是 className属性。

您的常量textContent 应按以下方式初始化:

const textContent = await page.evaluate(() => document.querySelector('.Body-body-qL80Q').textContent);