If you ask me and given that you’ve previous knowledge of web programming, I’d suggest you to read neither of them either. As far as I can guess, you should have a pretty good knowledge of basic html, css and javascript and that’ll do for now, you don’t need to waste more time. Or perhaps if you think you are not that competent yet, then you can from the point of view of taking a refresher, read the “Head First HTML5”. But do not concern yourself too much with third party tools/frameworks like jquery, concentrate on basic javascript, html and css only. A basic knowledge of OOP concepts would be very useful and necessary too.
There are a lot more essential concepts/technologies to learn if you want to be up and running with ionic development any soon. They are daunting all right but don’t be unnerved, it all boils down to how much you understand their underpinnings and how they all connect. The rest is basically coding, which you already know I believe. So over and above the knowledge of html5, css3 and javascript, here is a list of essential concepts/technologies/tools you should learn about right now:
Ionic 2+
The Ionic CLI
Angular 2+
TypeScript
Cordova
Node.js
NPM
SASS
And, give special importance to concepts like Modules, Annotations, Observables, Promises, Dependency Injection etc. when learning typescript.
Don’t worry too much though if these look daunting as I said, with some time and actual practice, all the concepts will sink in. Start with creating the sample ionic projects even if you don’t understand them yet. Try to learn the CLI tool. Then slowly and steadily, you’ll be up and running with ionic!
What you don’t need to learn (rather should avoid): Any version lesser than Ionic 2 and Angular 2.
A Bird’s Eye View might help you too, just an attempt of mine 
All the best!