Puppeteer:帧的内容不能读取属性为null

Question

My test html:

<div id="mainBlock">
<div  class="underBlock">
Hello!
</div>
</div>

我试着得到div的内容与类underBlock这样:

const puppeteer = require('puppeteer');
(async () => {
const browser = await puppeteer.launch({
headless:false,
});
const page = await browser.newPage();
let response =  await page.goto('http://localhost/TestPup/Index.html');
let block = await page.waitForXPath("//div[contains(@class,'underBlock')]")
let frame = await block.contentFrame()
console.log(frame.content())
await browser.close();
})();

but I got error:

TypeError: Cannot read property 'content' of null

Answer 1

据我了解，elementHandle.contentFrame()只返回iframe元素的一个帧，你有一个常规的div，它包含在主帧中，也就是在page中，里面没有帧。