| Feature | Bootstrap 3 | Bootstrap 4 | Bootstrap 5 |
|---|---|---|---|
| Glyphicons supported by default | Yes | No | No |
| Total icons | ~250 | - | - |
| Icon format | Font | - | - |
| How to add | Built-in | - | Via CDN |
| Icon syntax | <span class="glyphicon glyphicon-icon_name"></span> |
- | <i class="bi bi-icon_name"></i> |
| Alternatives | - | Font Awesome, Bootstrap Icons | Font Awesome, Bootstrap Icons |
| Built-in utility classes | Yes | - | - |
| Customization | Size, color utilities | - | Regular CSS |
| Accessibility | Alt text, semantic HTML | - | Alt text, semantic HTML |
| Animations | CSS transforms, transitions | - | CSS transforms, transitions |
| Responsive design | Icon scaling, visibility | - | Icon scaling, visibility |
This table summarizes some of the key differences between using Glyphicons in Bootstrap 3, Bootstrap 4, and Bootstrap 5. It highlights that while Glyphicons were built into Bootstrap 3, they have been removed from the latest versions. The table also shows some of the customization and accessibility best practices that still apply when using alternatives like Font Awesome or Bootstrap Icons.