Lightbox
A lightbox is a modal that displays an image or video in a full-screen overlay. It's great for things like clicking on thumbnails to view a larger image or video.
Image Lightbox
The simplest way to trigger a lightbox in reveal.js is to add the data-preview-image attribute to an img tag. Clicking on the image below, will open the same image in an overlay.
<img src="reveal.png" data-preview-image>
Lightboxes aren't limited to opening the image src. You can open any image you like by assigning a value to the data-preview-image attribute.
<img src="reveal.png" data-preview-image="mastering.svg">Video Lightbox
Video lightboxes work the same way as image lightboxes except you use the data-preview-video attribute instead.
<video src="video.mp4" data-preview-video></video>
<img src="reveal.png" data-preview-video="video.mp4">Lightbox Media Size
The sizing of media in the lightbox can be controlled using the data-preview-fit attribute. The following fit modes are supported:
| Value | Effect |
|---|---|
| scale-down (default) | Scale media down if needed to fit in the lightbox. |
| contain | Scale media up and down to fit the lightbox without cropping. |
| cover | Scale media to cover the entire lightbox, even if some of it is cut off. |
<img src="reveal.png" data-preview-image data-preview-fit="cover">
Works on Any Element
Note that the lightbox feature works on any element, not just images and videos. For example, you can trigger an image or video lightbox from clicking a button or link.
<a data-preview-image="image.png">📸 Open Logo</a>
<button data-preview-video="video.mp4">🎥 Open Video</button>Iframe Lightbox
It's also possible to preview links in iframe lightboxes. The syntax for this is slightly different from how image and video lightboxes work. To enable a link preview, you'll need to add the data-preview-link attribute to an anchor tag. It does not accept any value and will always use the anchor's href attribute as the source for the iframe.
<a href="https://hakim.se" data-preview-link>Open Hakim's Website</a>Note that this will only work if the link allows for embedding. Many domains prevent embedding via x-frame-options or Content-Security-Policy.
