[jQuery] Filtering charachter input with jquery/javascript

[Giovanni Battista Lenoci]

Hi, I'm having a problem filtering keyboard input in a text field.

Here is the page with the test:

http://lab.gianiaz.com/jquery/filter_input/

I use this function to catch the key pressed by the user:

function onlyNumbers(e) {

  key = e.keyCode;

  if(debug) log("onlyNumbers\nkey_code:"+key);

  if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) ||
(key==27) ) return true;

  keychar = String.fromCharCode(key);
  if(debug) log("keychar:"+keychar);

  // numbers
  if((("0123456789.,").indexOf(keychar) > -1)) {
    if(debug) log('OK');
    return true;
  }

  if(debug) log('KO');
  return false;

}

But If I press a number it works, when I press the "dot" or the
"comma" key I receive this:

onlyNumbers key_code:190
keychar:¾
KO
onlyNumbers key_code:188
keychar:¼
KO

Can you help me understand why it doensn't works?

Bye