OK you're on the right track but just need to change a few things.
- Firstly, I have no idea where your
afterJS variable comes from? Either way you won't need it.
- You're asking for data to be typed into the
username and password input fields but aren't asking puppeteer to actually click on the log in button to complete the log in process.
page.evaluate() is used to execute JavaScript code inside of the page context (ie. on the web page loaded in the remote browser). So you don't need to use it here.
I would refactor your code to look like the following:
const puppeteer = require('puppeteer');
(async () => {
const browser = await puppeteer.launch();
const page = await browser.newPage();
await page.goto('https://www.instagram.com/accounts/login/');
await page.waitForSelector('input[name="username"]');
await page.type('input[name="username"]', 'username');
await page.type('input[name="password"]', 'password');
await page.click('button[type="submit"]');
// Add a wait for some selector on the home page to load to ensure the next step works correctly
await page.pdf({path: 'page.pdf', format: 'A4'});
await browser.close();
})();
Hopefully this sets you down the right path to getting past the login page!
Update 1:
You've enquired about parsing the text of an element on Instagram... unfortunately I don't have an account on there myself so can't really give you an exact solution but hopefully this still proves of some value.
So you're trying to evaluate an elements text, right? You can do this as follows:
const text = await page.$eval(cssSelector, (element) => {
return element.textContent;
});
All you have to do is replace cssSelector with the selector of the element you wish to retrieve the text from.
Update 2:
OK lastly, you've enquired about scrolling down to an element within a parent element. I'm not going to steal the credit from someone else so here's the answer to that:
How to scroll to an element inside a div?
What you'll have to do is basically follow the instructions in there and get that to work with puppeteer similar to as follows:
await page.evaluate(() => {
const lastLink = document.querySelectorAll('h3 > a')[2];
const topPos = lastLink.offsetTop;
const parentDiv = document.querySelector('div[class*="eo2As"]');
parentDiv.scrollTop = topPos;
});
Bear in mind that I haven't tested that code - I've just directly followed the answer in the URL I've provided. It should work!