<form method="POST" action="--WEBBOT-SELF--">
  <p><input type="text" name="numero"
  onKeypress="if(event.keyCode> 95) && (event.keyCode< 106)) || ((event.keyCode> 47) && (event.keyCode< 58) event.returnValue = false;"
  size="24"> S� numeros</p>
  </p>
  <p><input type="submit" value="Submit" name="B1"></p>
</form>