How to call a javascript method on Keypress or Keydown

How to call method on keypress :

we can use
document.onkeypress = KeyCheck; or

document.onKeydown = KeyCheck;

// to perform operation on esc key press
function KeyCheck(e) {
var KeyID = (window.event) ? event.keyCode : e.keyCode;
if (KeyID == '27') // 27 is the key code for ESC key

{
// To do

}
}

Note : onKeypress wont work for safari browser so we can use onkeydown