DokuWiki caches a lot of stuff and there are several ways to trigger a cache refresh. Probably the easiest is to add "?purge=1" to any wiki url. For more details see page on
caching.
For JS and CSS updates you will most likely also need to force your web browser to refresh its cache. Shift+Refresh or Ctrl+Refresh is normally sufficient. Which one will work will depend on your browser and OS.