A BEGINNER’S JOURNEY
The jQuery library has been around for several years and has catapulted as one of the most used tools in the web developer’s belt. The reason for its vast usage is that it solves many of the cross-browser issues that creep up during development. The library is popular for both web developers and web designers. The community around jQuery is amazing and there are tons of jQuery plugins to choose from.
Inevitably you’ll need to support browsers that don’t support the native feature you are trying to use. Thankfully you can use Feature Detection to determine if the browser you are in implements that feature and if it doesn’t then you can provide functionality to mimic that feature (a.k.a. a polyfill or shim).
RESPONSIVE WEB DESIGN
Instead of implementing a different UI for mobile devices, tablets, and desktop browsers you can use responsive web design techniques to provide one experience that restructures the UI according to its size.
Hopefully the above resources will get you started in your transition to front-end web development. There is a lot to learn, but it is an exciting space that changes frequently. Having a desire to learn is a good trait to have in this field.
If you have any resources that you think I missed please add them in the comments and I’ll try to update the lists above if I think they are appropriate.