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Pros and Cons of Using pdf.js vs. Embedding Base64 PDFs in an <iframe>​

Using pdf.js, pros​

Customizability​

  • Allows full control over the rendering of the PDF (e.g., custom UI, annotations, etc.).
    Within the limitations of PDFjs
  • You can implement features like lazy loading1, page-specific rendering, and custom navigation.

Cross-Browser Consistency​

  • Ensures consistent rendering across all browsers, even those with limited or no built-in PDF support.

Performance Optimization​

  • Supports lazy loading of pages, rendering only the visible pages, which is useful for large PDFs.
  • Allows fine-grained control over memory usage and rendering performance.

Advanced Features​

  • Enables advanced features like text extraction, searching, and highlighting within the PDF.
  • Can integrate with other libraries for annotations, signatures, or custom interactions.
  • No Dependency on Browser PDF Viewer: Works even in environments where the browser's built-in PDF viewer is disabled or unavailable.

Using pdf.js, cons​

Complexity​

  • Requires additional setup and maintenance of the pdf.js library.
  • More code to manage, especially for custom features.

Performance Overhead​

  • Rendering PDFs in JavaScript can be slower compared to native browser rendering.
  • May consume more memory and CPU, especially for large or complex PDFs.

Dependency​

  • Relies on a third-party library, which may introduce compatibility issues or require updates.

Embedding Base64 PDFs in an <iframe>, pros​

Simplicity​

  • Requires minimal code to implement. Just set the src attribute of the <iframe> to the Base64-encoded PDF.
  • Leverages the browser's built-in PDF viewer, reducing the need for custom development.

Performance​

  • Native browser PDF viewers are optimized for performance and memory usage.
  • Offloads rendering to the browser, freeing up JavaScript resources.

Compatibility​

  • Works seamlessly with modern browsers that have built-in PDF viewers (e.g., Chrome, Edge, Firefox).

No Third-Party Dependency​

  • Does not require any external libraries, reducing the risk of dependency-related issues.

Embedding Base64 PDFs in an <iframe>, cons​

Limited Customization​

  • You cannot customize the PDF viewer's UI or behavior (e.g., zoom controls, navigation).
  • No control over how the PDF is rendered or displayed.

Browser Dependency​

  • Relies on the browser's built-in PDF viewer, which may not be available or consistent across all browsers. Some browsers (e.g., older versions of Safari or Internet Explorer) may not support embedded PDFs.

No Advanced Features​

  • Cannot implement features like text extraction, annotations, or custom interactions.
  • Limited to the functionality provided by the browser's PDF viewer.

When to Use Each Approach​

Use pdf.js​

  • When you need advanced features like text extraction, annotations, or custom UI.
  • When you want consistent behavior across all browsers.
  • When dealing with large PDFs where lazy loading or page-specific rendering is important.

Use <iframe> with Base64​

  • When simplicity and minimal setup are priorities.
  • When you don't need customization or advanced features.
  • When targeting modern browsers with reliable built-in PDF viewers.

Recommendation​

If your application requires a highly interactive and customizable PDF viewer, go with pdf.js. However, if you just need to display PDFs quickly and without much effort, embedding them in an <iframe> is a simpler and more efficient solution.

Footnotes​

  1. Lazy loading is a design pattern that delays the loading of resources, such as images, videos, or data, until they are needed. This approach improves performance by reducing initial load times and conserving system resources, as only the content currently visible or required by the user is loaded. For example, in a PDF viewer, lazy loading can render only the pages currently being viewed, rather than loading the entire document at once. ↩