Web Form Automation

Automate web form interactions including login, file upload, text input, and form submission using Playwright. Use when user needs to automate website interactions, upload files to web forms, fill out forms with text input, click buttons, or submit data to web applications. Supports session management via cookies, compressed image uploads (webp), and proper event triggering for reliable form submission.

Automate web form interactions reliably using Playwright with best practices for session management, file uploads, and form submission.

Quick Start

const { chromium } = require('playwright');

// Basic form automation
const browser = await chromium.launch({ headless: true });
const page = await browser.newPage();
await page.goto('https://example.com/form');

// Upload compressed images
await page.locator('input[type="file"]').setInputFiles('/path/to/image.webp');

// Type text (triggers events properly)
await page.locator('textarea').pressSequentially('Your text', { delay: 30 });

// Submit form
await page.locator('button[type="submit"]').click({ force: true });

Session Management

Using Browser Session Data

When user provides a JSON file with session data:

const sessionData = JSON.parse(fs.readFileSync('session.json', 'utf8'));

// Set cookies before navigating
for (const cookie of sessionData.cookies || []) {
  await context.addCookies([cookie]);
}

// Set localStorage/sessionStorage
await page.evaluate((data) => {
  for (const [k, v] of Object.entries(data.localStorage || {})) {
    localStorage.setItem(k, v);
  }
}, sessionData);

File Upload Best Practices

Image Compression

Always compress images before upload for reliability:

# Convert to webp for best compression
convert input.png output.webp

# Or resize if needed
convert input.png -resize 1024x1024 output.webp

Size comparison:

• Original PNG: ~4MB
• Compressed PNG: ~1MB
• WebP: ~30-50KB (99% smaller)

Upload Sequence

// 1. Find file inputs
const fileInputs = await page.locator('input[type="file"]').all();

// 2. Upload with waiting time
await fileInputs[0].setInputFiles('/path/to/start.webp');
await page.waitForTimeout(3000); // Wait for upload to process

await fileInputs[1].setInputFiles('/path/to/end.webp');
await page.waitForTimeout(3000);

Text Input Best Practices

Use pressSequentially, not fill()

❌ Don't use fill() - doesn't trigger input events:

await textInput.fill('text'); // May not activate submit button

✅ Use pressSequentially() - simulates real typing:

await textInput.pressSequentially('text', { delay: 30 });

Trigger Events Manually (if needed)

await page.evaluate(() => {
  const el = document.querySelector('textarea');
  el.dispatchEvent(new Event('input', { bubbles: true }));
  el.dispatchEvent(new Event('change', { bubbles: true }));
});

Button Clicking

Force Click When Disabled

If button appears disabled but should be clickable:

await button.click({ force: true });

Check Button State

const isEnabled = await button.isEnabled();
const isVisible = await button.isVisible();

Complete Example: Video Generation Form

const { chromium } = require('playwright');
const fs = require('fs');

async function submitVideoForm(sessionFile, startImage, endImage, prompt) {
  const browser = await chromium.launch({ 
    headless: true, 
    args: ['--no-sandbox'] 
  });
  const context = await browser.newContext();
  const page = await context.newPage();
  
  // Load session if provided
  if (fs.existsSync(sessionFile)) {
    const session = JSON.parse(fs.readFileSync(sessionFile, 'utf8'));
    // Set cookies, localStorage...
  }
  
  // Navigate
  await page.goto('https://example.com/video', { 
    waitUntil: 'domcontentloaded' 
  });
  await page.waitForTimeout(3000);
  
  // Upload images (webp compressed)
  const inputs = await page.locator('input[type="file"]').all();
  await inputs[0].setInputFiles(startImage);
  await page.waitForTimeout(3000);
  await inputs[1].setInputFiles(endImage);
  await page.waitForTimeout(3000);
  
  // Select options
  await page.click('text=Seedance 2.0 Fast');
  await page.click('text=15s');
  
  // Type prompt
  const textarea = page.locator('textarea').first();
  await textarea.pressSequentially(prompt, { delay: 30 });
  await page.waitForTimeout(2000);
  
  // Submit
  await page.locator('button[class*="submit"]').click({ force: true });
  
  // Wait and screenshot
  await page.waitForTimeout(5000);
  await page.screenshot({ path: 'result.png' });
  
  await browser.close();
}

Scripts

The scripts/ directory contains reusable automation scripts:

• webp-compress.sh - Convert images to webp format
• form-submit.js - Generic form submission template

Troubleshooting

Button stays gray/disabled

• Wait longer after file upload (3+ seconds)
• Ensure text input triggers events (use pressSequentially)
• Check if images are still uploading

Upload times out

• Compress images to webp format first
• Reduce image dimensions if very large

Form doesn't submit

• Use force: true for click
• Check button selector is correct
• Verify all required fields are filled