How to Bypass CAPTCHA in JavaScript

[CAPTCHAFORUM]

https://2captcha.com/blog/how-to-use-javascript-to-bypass-captcha

CAPTCHA is a widely used security mechanism designed to prevent bots from interacting with web pages. However, if you're developing an automated system for legitimate purposes (such as web scraping or automated form submission), you may need to bypass CAPTCHA challenges. One of the most effective solutions is to use an external CAPTCHA-solving service like 2Captcha.

In this guide, we'll walk through the process of bypassing CAPTCHA using JavaScript and the 2Captcha API.

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1. Understanding How CAPTCHA Works​

Before diving into the bypass process, it’s important to understand how CAPTCHA systems function. The most common type is Google reCAPTCHA, which comes in different versions:

• reCAPTCHA v2 (Checkbox) - Requires users to tick a box.
• reCAPTCHA v2 (Invisible) - Triggers verification based on user interaction.
• reCAPTCHA v3 - Assigns a score based on user behavior.

Each reCAPTCHA challenge embeds a site key into the webpage, which is essential for solving it.

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2. Finding the Site Key​

To interact with reCAPTCHA, you need to locate the site key. This is usually present in the webpage’s HTML and looks like this:

<script src="https://www.google.com/recaptcha/api.js" data-sitekey="6LcA...X"></script>

Extract and save the data-sitekey value as you’ll need it for solving the CAPTCHA.

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3. Using 2Captcha to Solve CAPTCHA​

2Captcha is a CAPTCHA-solving service that employs human workers to solve CAPTCHA challenges and return the response token.

Step 1: Create an Account on 2Captcha​

Sign up at 2Captcha and obtain your API key from the dashboard.

Step 2: Install Required Dependencies​

You'll need Axios for making HTTP requests. If you're working in a Node.js environment, install Axios with:

npm install axios
For browser-based JavaScript, you can include it via CDN:

<script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>

Step 3: Submitting CAPTCHA for Solving​

Send the site key and page URL to 2Captcha to request a solution.

const axios = require('axios');

const API_KEY = 'your_2captcha_api_key';
const SITE_KEY = 'site_key_from_target_website';
const PAGE_URL = 'https://targetwebsite.com';

async function solveCaptcha() {
try {
// Submit CAPTCHA for solving
let response = await axios.post('http://2captcha.com/in.php', null, {
params: {
key: API_KEY,
method: 'userrecaptcha',
googlekey: SITE_KEY,
pageurl: PAGE_URL,
json: 1
}
});

let requestId = response.data.request;
console.log('CAPTCHA request submitted:', requestId);

// Wait for the solution
await new Promise(resolve => setTimeout(resolve, 15000));

while (true) {
let result = await axios.get(`http://2captcha.com/res.php?key=${API_KEY}&action=get&id=${requestId}&json=1`);

if (result.data.status === 1) {
console.log('CAPTCHA solved:', result.data.request);
return result.data.request;
}

console.log('Waiting for CAPTCHA solution...');
await new Promise(resolve => setTimeout(resolve, 5000));
}
} catch (error) {
console.error('Error solving CAPTCHA:', error);
}
}

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4. Submitting the CAPTCHA Solution​

Once 2Captcha provides the solution, submit it to the target website.

async function submitCaptchaSolution(token) {
    let formData = new FormData();
formData.append('g-recaptcha-response', token);

let response = await axios.post(PAGE_URL, formData);
console.log('Form submission response:', response.data);
}

solveCaptcha().then(submitCaptchaSolution);

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5. Automating the Entire Process​

To integrate CAPTCHA solving into a fully automated system, follow these steps:

1. Intercept webpage requests using Puppeteer or Selenium.
2. Extract the site key dynamically from the page.
3. Solve CAPTCHA using 2Captcha as shown above.
4. Inject the response token into the webpage and submit the form programmatically.

For example, with Puppeteer:

const puppeteer = require('puppeteer');

(async () => {
const browser = await puppeteer.launch({ headless: false });
const page = await browser.newPage();
await page.goto(PAGE_URL);

let token = await solveCaptcha();
await page.evaluate((captchaToken) => {
document.querySelector('[name="g-recaptcha-response"]').value = captchaToken;
}, token);

await page.click('#submit-button'); // Adjust selector as needed
await browser.close();
})();

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By leveraging JavaScript and 2Captcha, you can efficiently bypass CAPTCHA challenges in an automated environment. However, always ensure that your automation complies with legal and ethical standards to avoid misuse.

With this approach, you can integrate CAPTCHA solving into web scraping, automated testing, and bot-driven workflows while minimizing manual intervention.