My android app killed when the back is press

Questions
1

i would like to know why my app is killed when i press the back button on my android phone

2

it is because the pages are loaded via ajax and the main app does not change. if you hit the button your phone will jump to the previous page … i put this little code in my js code. that kills the history and so yout button has no page to jump to…

// History killer
history.pushState(null, null, location.href);
    window.onpopstate = function () {
	history.go(1);
    };
3

Thanks
it was google map plugin which was causing that