Código HTML:
<form action="control.php" method="POST"> <table align="center" width="225" cellspacing="2" cellpadding="2" border="0"> <tr> <td colspan="2" align="center" <? if ($_GET["errorusuario"]=="si") { ?> bgcolor="#cccccc"><span style="color:ffffff"><b>Datos incorrectos</b></span> <? } else { ?> bgcolor="#cccccc">Introduce tu clave de acceso <? } ?> </td> </tr> <tr> <td align="right">USER:</td> <td><input type="Text" name="usuario" size="8" maxlength="50"></td> </tr> <tr> <td align="right">PASSWD:</td> <td><input type="password" name="contrasena" size="8" maxlength="50"></td> </tr> <tr> <td colspan="2" align="center"><input type="Submit" value="ENTRAR"></td> </tr> </table> </form>