Function Onkeypress for cursor key

[newphpcoder]

Good day!

In my javascript code I have a function for the enter key. I want to add cursor key in that function/ I research about the coding for cursor key but I can't find the code same on what I want to happen.

Here is the code:

<script language="javascript">
  function handleEnter(e, nextfield)
        {
        var characterCode = (e && e.which)? e.which: e.keyCode;
        if(characterCode == 13)
            {
            document.getElementById(nextfield).focus();
            return false;
            } 
        else
            {
            return true;
            }
        }
    </script>
<input type='text' name='plt' onkeypress='return handleEnter(event,\"b0\");' />

Thank you

[Dormilich]

arrow keys are 37 to 40 (cf.)