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)
            return false;
            return true;
<input type='text' name='plt' onkeypress='return handleEnter(event,\"b0\");' />
Thank you