borrar podria ser algo asi?
begin
textfield1.clear;
textfield2.clear;
echo $suma:='';
textfield11.setfocus;
end;
Cerrar
close;
<html>
<head>
<title>Botones PHP</title>
</head>
<body>
<form name="form1" method="post" action="boton.php">
ingrese nro:
<input name="textfield1" type="text" size="10">
<br>
<br>
ingrese nro:
<input name="textfiel2" type="text" size="10">
<br>
<br>
<input type="submit" name="Submit" value="Calcular">
<input type="submit" name="Submit2" value="Borrar">
<input type="submit" name="Submit3" value="Cerrar">
</form>
</body>
</html>
![](http://www.subirimagenes.com/imagenes/previo/thump_1317672php_botones.gif)
Saludos