Client-side scripting, a bit of history, some JavaScript, and ending with jQuery. Personal opinions about JavaScript aside, it is a great way to add some interactivity and spice to your websites.
Some useful links:
* https://developer.mozilla.org/en-US/d...
* https://www.w3schools.com/Js/
* https://learn.jquery.com/
* https://www.w3schools.com/jquery/