Which device platform are you using? On iOS, please see comments in Daniel Van Leeuwen's link above. https://cw.sdn.sap.com/cw/docs/DOC-150957
For Android, although Android 4.4 is not officially supported yet, you can achieve the same line by line on-device/simulator debugging as iOS using Android 4.4 simulator. https://developers.google.com/chrome-developer-tools/docs/remote-debugging#debugging-webviews
Thanks,
Andrew.