Imp: event to occur immediately on checking checkbox: points assured

hi all,

I am working on a module pool prog . There is a single screen 0900 on which i have a checkbox 'CHK' and two input fields 'IP1' and 'IP2'.

I have a requirement where i need an event to occur immediately on checking the checkbox on screen without the press of any key.

Also i have a separate requirement where i need that the data entered into IP1 is immediately copied to IP2 without pressing enter or any other key.

Points assured

thanks in advance