The forums ran from 2008-2020 and are now closed and viewable here as an archive.
Case Matters ( btnsmaller_onclick != btnSmaller_onclick).
Use a console (e.g., firebug or chrome dev tools). It’ll point out simple stuff like this for you.
Frontend Masters is the best place to get it. They have courses on all the most important front-end technologies, from React to CSS, from Vue to D3, and beyond with Node.js and Full Stack.