Iphone or Android jogapp?
If it possible to build a Workspace with only the jogapp and display this in my iphone as
Webapp? Then i can controll the machine parallel to my browser workspace?
Absolutely it is possible. Nobody has done one specific to jogging. The whole reason I did the Touch Jog add-on to the Axes widget was to set it up for use on a touch screen on a phone. How does that feature work on your iPhone? There have also been 2 attempts at minified workspaces by two different users. The most recent one is http://chilipeppr.com/grbl-min
Hmm, cool but the buttons look not so nice. I’ll send a
Screenshot. Can u give me the second url?
This looks better 
if it possible to connect the json server from 2 workspaces at the same time?
Connecting SPJS from 2 or more workspaces at the same time is 100% absolutely supported and in fact is one of the core design principles of SPJS so that the CNC world has one of the most sophisticated elements in its arsenal well beyond anything available today including Mach 3.
i know some folks use touch screens with Mach 3 or other interfaces… i wonder if jquery-mobile could be added in to make the buttons and fields touch friendly and a tablet or touch-screen monitor interface developed… hmm…