Lazy Loading Iframes and Videos

Introduction

Lazy loading is a design pattern that postpones the loading of resources until they are needed, which can significantly enhance the performance of web applications. This lesson covers lazy loading for iframes and videos, two media types that often consume significant bandwidth and resources.

What is Lazy Loading?

Lazy loading means that content such as images, iframes, and videos are not loaded until they are in the viewport or about to enter the viewport. This helps reduce initial load time and improves the user experience.

Why Lazy Load?

How to Lazy Load Iframes and Videos

Lazy Loading Iframes

To implement lazy loading for iframes, use the `loading` attribute set to `lazy`:

<iframe src="https://example.com" loading="lazy" width="600" height="400"></iframe>

Lazy Loading Videos

For videos, you can use the `loading` attribute as well, or employ JavaScript to load the video only when the user interacts with it:

<video width="600" height="400" controls loading="lazy">
  <source src="video.mp4" type="video/mp4">
  Your browser does not support the video tag.
</video>

Best Practices

• Always use the `loading` attribute when available.
• Implement a placeholder image or a play button for videos.
• Test lazy loading across different devices and browsers.
• Consider using Intersection Observer for more complex lazy loading scenarios.

FAQ