I’m using DHTMLX with phonegap. Works well once you get around some quirks. 
Full screen on the iPhone will depend upon the wether you have got rid of the status bar. See here (Removing the Status / Carrier bar in xCode)
If you perform the above, you get a gap at the bottom as the screen has shifted up 20 px
Full screen height with StatusBar = 300,460
Full Screen height without Status Bar = 320,480
I needed to adjust the touchui.js to get the true full screen with no gap at the bottom.
The code I changed was:
dhx.ui.orientation?(a=480,b=e?268:300):(a=320,b=e?416:460)
to
dhx.ui.orientation?(a=480,b=e?268:320):(a=320,b=e?416:480)
I hope this helps someone.
Cheers
Joe