I've found my solution. I need to work on keypress event in opera.
Opera can't output the correct code in keypress event ( it gives 46 for both delete and dot button). But in keydown event it gives the correct code. So at first i detected if it were an opera browser, then i took the keycode from keydown event, saved in a variable and finally in keypress performed my tasks.
For other browsers the code will run normally in keydown event. Opera is an exception. You can find the code at: [code.google.com ]