HTML5 mobile frameworks like Ionic in general do work on desktop as well. Ionic will work on desktop but it is specifically designed for iOS / Android.
The problem with desktop is that you can’t use any Cordova plugins (like the Camera plugin). The Cordova plugins won’t be available until you compile with Cordova and install on a device. If you don’t want access to any native plugins then it will run on mobile / desktop fine. (btw, although typically a plugin is used to access the native Camera API, it is also possible to access the camera through plain HTML5, check this out: http://www.html5rocks.com/en/tutorials/getusermedia/intro/)