Convert HTML to PDF in JavaScript with html2pdf.js

Generating a PDF from HTML is a classic problem in web development. Whether you're creating invoices, reports, or data summaries, the ability to "Save as PDF" client-side is a powerful feature for any application.

In this guide, we'll look at how to use html2pdf.js for lightweight client-side conversion and when it makes sense to move to a specialized tool like the Aoexl SDK.

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Why Choose html2pdf.js?

html2pdf.js is a popular client-side library that combines html2canvas (for taking a screenshot of your DOM) and jsPDF (for packaging that image into a PDF).

Key Advantages:

• Zero Server Overhead: The conversion happens entirely in the user's browser.
• Easy Setup: One script tag is often all you need.
• Customizable: You can set margins, image quality, and page orientation easily.

Getting Started with html2pdf.js

1. Include the Library

You can load it via CDN:

<script src="https://cdnjs.cloudflare.com/ajax/libs/html2pdf.js/0.12.1/html2pdf.bundle.min.js"></script>

2. Basic Implementation

Suppose you have a div with the ID invoice. Here is how you convert it:

const element = document.getElementById('invoice');
const options = {
  filename:     'invoice_123.pdf',
  margin:       [10, 10], // top, left in mm
  image:        { type: 'jpeg', quality: 0.98 },
  html2canvas:  { scale: 2 },
  jsPDF:        { unit: 'mm', format: 'a4', orientation: 'portrait' }
};

// Generate and save
html2pdf().set(options).from(element).save();

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When to Move Beyond html2pdf.js

While html2pdf.js is great for simple exports, it has inherent limitations due to its "image-screenshot" approach:

1. Non-Selectable Text: Since it renders the HTML as a canvas image, the resulting PDF often lacks selectable text or clickable links.
2. CSS Limitations: Complex layouts (Grid, Flexbox, or advanced CSS3) may not render perfectly.
3. Large Documents: Rendering 100+ pages client-side will consume significant browser memory and may crash on mobile devices.
4. Interactive Features: If you need fillable form fields, digital signatures, or advanced encryption, a specialized PDF partner is required.

The Aoexl Advantage

For production applications where document fidelity and interactive features are critical, the Aoexl SDK provides a professional alternative.

Professional HTML-to-PDF Conversion

Aoexl uses a headless browser engine to render HTML, ensuring that your PDFs look exactly like your web pages—with selectable text, vector graphics, and full CSS3 support.

import { AoexlAPI } from '@aoexl/client';

async function generateProfessionalPdf(htmlContent) {
  const response = await fetch('/api/aoexl/generate', {
    method: 'POST',
    body: JSON.stringify({ html: htmlContent })
  });
  
  const pdfBlob = await response.blob();
  const url = URL.createObjectURL(pdfBlob);
  window.open(url);
}

Key Differences at a Glance

Feature	html2pdf.js	Aoexl SDK
Text Type	Raster Image	High-fidelity Vector (Selectable)
CSS Support	Basic	Full CSS3 / Flexbox / Grid
Forms	No	Yes (Fillable fields)
Signatures	No	Yes (Draw, Type, Upload)
Scale	Desktop Browser	Cloud & Mobile Optimized

Conclusion

If you need a quick "Save as Image-PDF" button for a single-page invoice, html2pdf.js is an excellent, free tool. However, if your users expect professional, searchable PDFs with complex layouts or signing capabilities, integrating the Aoexl SDK will save you significant engineering time and provide a superior end-user experience.

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• Browse Aoexl Developer Docs
• Try the Hosted Signing Demo
• Contact the Aoexl Team