Drupal has a solid Ajax interface, we can hook into the Ajax events at various places. I will explain some 5 important methods,
 
1) beforeSerialize - called before data is packed and runs before the beforeSend & beforeSubmit
2) beforeSubmit - called before the ajax request
3) beforeSend - called just before the ajax request
4) success - called after ajax event returns data
5) complete - called after the request ends
 
Lets say you want to capture some ajax event (in built or made by other module) to do some event like Views refresh. We can use a very simple logic to do that.