Some web-based frameworks, such as Django, support detecting module changes and reloading them on the fly. However, although the same as hotswapping for most intents and purposes, this is technically just a cache purge, triggered by a new file. This does not apply to markup and programming languages such as HTML and PHP respectively, in the general case, as these files are normally re-interpreted on each use by default. There are a few CMSs and other PHP-based frameworks (such as Drupal) that employ caching, however. In these cases, similar abilities and exceptions apply.