How to Build a PDF to Image Converter with JavaScript
Learn how to create a client-side PDF to Image Converter using HTML, CSS, and JavaScript. Supports PNG, JPEG, WebP, DPI control, grayscale, batch processing, page ranges, and more.
Table of contents [Show]
What You’ll Build
A web-based tool that allows users to:
- Upload or drag-and-drop a PDF file
- Set a user and owner password
- Encrypt the file using AES128 encryption
- Instantly download the secured PDF
Key Features
✅ Drag & Drop Upload
✅ AES128 PDF Encryption
✅ User and Owner Password Protection
✅ PDF.co API Integration for Cloud Security
✅ Responsive UI with Modern Design
✅ Instant Download Link
Technologies Used
- HTML5 – Clean, semantic layout
- CSS3 – Responsive and modern design
- JavaScript – Handles file uploads, API communication, and UI logic
- PDF.co API – Cloud-based PDF processing with encryption support
📄 Full Source Code:
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<title>PDF Password Maker</title>
<link rel="stylesheet" href="style.css" />
</head>
<body>
<div class="container">
<h1>🔐 PDF Password Maker</h1>
<form id="pdfForm">
<div class="drop-zone" id="dropZone">
<p>📁 Drag & Drop PDF or <label for="fileInput" class="browse-btn">Browse</label></p>
<input type="file" id="fileInput" accept="application/pdf" hidden />
</div>
<input type="password" id="userPassword" placeholder="User Password" required />
<input type="password" id="ownerPassword" placeholder="Owner Password" required />
<button type="submit">Protect PDF</button>
</form>
<div id="downloadSection" style="display: none;">
<p>✅ PDF protected! <a id="downloadLink" href="#" download>Download here</a></p>
</div>
</div>
<script src="script.js"></script>
</body>
</html>
style.css
body {
font-family: Arial, sans-serif;
background: #f0f4f8;
display: flex;
justify-content: center;
padding: 40px;
}
.container {
background: white;
padding: 30px;
border-radius: 16px;
box-shadow: 0 8px 24px rgba(0,0,0,0.1);
width: 100%;
max-width: 500px;
text-align: center;
}
h1 {
margin-bottom: 20px;
}
.drop-zone {
border: 2px dashed #ccc;
padding: 30px;
border-radius: 12px;
margin-bottom: 20px;
background-color: #fafafa;
cursor: pointer;
}
.browse-btn {
color: #007bff;
cursor: pointer;
text-decoration: underline;
}
input[type="password"] {
width: 100%;
padding: 12px;
margin: 10px 0;
border-radius: 8px;
border: 1px solid #ccc;
}
button {
background-color: #007bff;
color: white;
border: none;
padding: 12px 20px;
border-radius: 8px;
cursor: pointer;
}
button:hover {
background-color: #0056b3;
}
script.js
const form = document.getElementById('pdfForm');
const fileInput = document.getElementById('fileInput');
const dropZone = document.getElementById('dropZone');
const downloadSection = document.getElementById('downloadSection');
const downloadLink = document.getElementById('downloadLink');
let selectedFile = null;
// Drag & drop events
dropZone.addEventListener('click', () => fileInput.click());
dropZone.addEventListener('dragover', (e) => {
e.preventDefault();
dropZone.style.borderColor = "#007bff";
});
dropZone.addEventListener('dragleave', () => {
dropZone.style.borderColor = "#ccc";
});
dropZone.addEventListener('drop', (e) => {
e.preventDefault();
dropZone.style.borderColor = "#ccc";
selectedFile = e.dataTransfer.files[0];
});
// Browse file input
fileInput.addEventListener('change', () => {
selectedFile = fileInput.files[0];
});
form.addEventListener('submit', async (e) => {
e.preventDefault();
if (!selectedFile) {
alert("Please upload a PDF file.");
return;
}
const userPassword = document.getElementById('userPassword').value;
const ownerPassword = document.getElementById('ownerPassword').value;
const apiKey = 'YOUR_PDFCO_API_KEY_HERE';
const formData = new FormData();
formData.append('name', selectedFile.name);
formData.append('file', selectedFile);
formData.append('ownerPassword', ownerPassword);
formData.append('userPassword', userPassword);
formData.append('encryptionAlgorithm', 'AES128');
try {
const response = await fetch('https://api.pdf.co/v1/pdf/security/add', {
method: 'POST',
headers: {
'x-api-key': apiKey
},
body: formData
});
const data = await response.json();
if (data.error) {
alert('Error: ' + data.message);
} else {
downloadSection.style.display = 'block';
downloadLink.href = data.url;
}
} catch (err) {
console.error(err);
alert("Something went wrong. Check console for more info.");
}
});Notes:
- Replace
'YOUR_PDFCO_API_KEY_HERE'with your actual API key. - This example uses AES128 encryption as specified.
- PDF.co's API handles all secure file processing.
How It Works
- The user uploads or drags a PDF file into the web app.
- They enter a user password (to open the file) and an owner password (to manage permissions).
- On submit, the PDF is securely uploaded to PDF.co’s encryption API.
- The response includes a protected PDF URL, ready for download.
Security: Why Use AES128?
AES128 is a trusted industry-standard encryption method. It's strong enough for most use cases, providing reliable protection without significantly increasing file size or processing time.
PDF.co ensures:
- Files are deleted after processing
- HTTPS secure endpoints
- AES128/256 support
- GDPR and HIPAA-compliant handling
Tips & Best Practices
- Never hard-code your API key in public-facing apps. Use a backend proxy for production.
- Encourage users to set strong passwords (mix of upper/lowercase, numbers, symbols).
- You can enhance the UI using frameworks like TailwindCSS or Bootstrap.
Conclusion
This project is a perfect example of how modern web technologies can create secure, user-friendly tools. By combining HTML, CSS, JavaScript, and cloud APIs, you can offer real-world functionality with minimal effort.
Start protecting your PDFs today — build it, host it, and help users stay safe!
