in the past I've used Phonegap in order to run my Javascript HTML CSS code on mobile devices.
Can I do the same thing with ionic?
From what I understand so far from Ionic :
You build your app with HTML/SASS/AngularJS/ui-router, so it's still the same process, Cordova parsing and "turning" a web app into a native one.
Ionic CLI provides simulators launching (iDevices simulators require OS X XCode, Android simulators require GenyMotion) with optional livereload, physical devices (just plug them), and desktop web browser also with livereload.
I think you can have the livereload simultaneously on a device simulator and the web browser, and possibly a physical device, so you're continually testing/debugging as you code.
Ionic uses Cordova (aka Phonegap). Ionic is the user interface controls for hybrid apps, which still use Cordova to build to mobile devices.
You can preview your app while you build on your desktop by using the Ionic CLI. http://ionicframework.com/docs/cli/install.html
ionic serve