How to un register default keybord shortcut keys

Hi,

I wanted to use my application with the all keyboard shortcuts only.

When I am trying to register the keys, I am facing below problems:

1) Some keys are already registered by the browser for some purpose. So, How can i un register that and register or my purpose.

Example: Ctrl+P( For print ) How can i use the same key for other purpose.

2) I am getting many focus problems. So, How can i manage the same.

3) If i don't want the focus to go out of my application then what should i need to do. Which means When i start pressing tab, focus is going to the URL as well.

Please provide me the solutions for the above.

Thanks,
Bhaskar