I've just integrated it in my app as a HTML5 game... not as a PhoneGap one and it works right.
If you wanna test it, you must try it on a mobile device or you can just use the google chrome emulator to emulate mobile devices.
You can follow this tutorial to learn how to implement leadbolt on a construct2 game: https://www.scirra.com/tutorials/740/ho ... ur-appgame
When setting the size of the ads in the leadbolt portal, set it to auto stretch so you have no problems with different mobile devices.