Do you want to develop add-on's for Firefox? Mozilla's Add-on SDK let's you create Firefox add-ons using standard Web technologies: JavaScript, HTML, and CSS. Recently I stumbled across Alexander Saladrigas's videos tutorials that teach Firefox add-ons development with Add-on SDK. The videos introduce you to the tools for creating, running, testing and packaging add-ons and working with buttons, panels and tabs.

Thank you Alexander for making these videos. Hope to see more from you in future.

http://playingwithsid.blogspot.com/2015/08/develping-firefox-add-ons-video-tutorial.html