************************************************
*                calendario.css                *   
************************************************

/* CSS Document */
.calendario_tabela{
	font-family:monospace;
	font-size:10px;
	border:1px solid #999999;
	background:#F5F5F5;
}
.calendario_dias{
	background:#FFFFFF;
	padding:2px;
}
.calendario_dias_hoje{
	background:#C0C0C0;
	padding:2px;
}
.calendario_semana{
	background:#999999;
	color:#FFFFFF;
	text-align:center;
	font-weight:bold;	
}
.calendario_hoje{
	font-weight:bold;
}
.calendario_mes_ano{
	text-align:center;
	font-weight:bold;
	color:#666666;
}
.calendario_links{
	color:#000000;
	display:block;
	text-decoration:none;
}
.calendario_links:hover{
	text-decoration:none;
	background:#999999;
	color:#FFFFFF;
}
.calendario_links_hoje{
	color:#FF0000;
	display:block;
	text-decoration:none;
}
.calendario_links_hoje:hover{
	text-decoration:none;
	background:#F0F0F0;
	color:#FFFFFF;
}

a:link {
  font-family:     monospace;
  font-size:       12px;
  text-decoration: none;
  color:           #000000;
}
a:visited {
  font-family:     monospace;
  font-size:       12px;
  text-decoration: none;
  color:           #000000;
}
a:hover {
  font-family:     monospace;
  font-size:       12px;
  text-decoration: underline;
  color:           #000000;
}
a:active {
  font-family:     monospace;
  font-size:       12px;
  text-decoration: none;
  color:           #0000000;
}

************************************************
*                calendario.php                * 
************************************************

<link rel="stylesheet" type="text/css" href="calendario.css">
<? 
class calendario{ 
  var $mes = array(
                   '01' => 'JANEIRO',
                   '02' => 'FEVEREIRO',
                   '03' => 'MARÇO',
                   '04' => 'ABRIL',
                   '05' => 'MAIO',
                   '06' => 'JUNHO',
                   '07' => 'JULHO',
                   '08' => 'AGOSTO',
                   '09' => 'SETEMBRO',
                   '10' => 'OUTUBRO',
                   '11' => 'NOVEMBRO',
                   '12' => 'DEZEMBRO'
                  );

  function mes_anterior($dia,$mes,$ano){
    if($mes == 1){
       $man = 12;
       $aan = $ano - 1;
    } else {
       $man = $mes - 1;
       $aan = $ano;
    }

    $val = checkdate($man,$dia,$aan);
    if($val == 0){
      $dia = 1;
    }
    echo '<a href="calendario.php?data='.sprintf("%02.0f",$dia).'/'.sprintf("%02.0f",$man).'/'.$aan.'">«</a>';
  }

  function mes_proximo($dia,$mes,$ano){
    if($mes == 12){
       $mpr = 1;
       $apr = $ano + 1;
    } else {
       $mpr = $mes + 1;
       $apr = $ano;
    }

    $val = checkdate($mpr,$dia,$apr);
    if($val == 0){
      $dia = 1;
    }
    echo '<a href="calendario.php?data='.sprintf("%02.0f",$dia).'/'.sprintf("%02.0f",$mpr).'/'.$apr.'">»</a>';
  }

  function ano_anterior($dia,$mes,$ano){
    $aan = $ano - 1;
    echo '<a href="calendario.php?data='.sprintf("%02.0f",$dia).'/'.sprintf("%02.0f",$mes).'/'.$aan.'">«</a>';
  }

  function ano_proximo($dia,$mes,$ano){
    $apr = $ano + 1;
    echo '<a href="calendario.php?data='.sprintf("%02.0f",$dia).'/'.sprintf("%02.0f",$mes).'/'.$apr.'">»</a>';
  }
  
  function cria($data){
    $arr = explode("/",$data);
    $dia = $arr[0];
    $mes = $arr[1];
    $ano = $arr[2];

    if(($dia == '') OR ($mes = '') OR ($ano = '')){
      $data = date("d/m/Y");
      $arr = explode("/",$data);
      $dia = $arr[0];
      $mes = $arr[1];
      $ano = $arr[2];
    }

    $arr = explode("/",$data);
    $dia = $arr[0];
    $mes = $arr[1];
    $ano = $arr[2];

    $val = checkdate($mes,$dia,$ano); // Verifica se a data é válida
    if($val == 1){
      $ver = date('d/m/Y', mktime(0,0,0,$mes,$dia,$ano));
    } else {
      $ver = date('d/m/Y', mktime(0,0,0,date(m),date(d),date(Y)));
    }

    $arr = explode("/",$ver);
    $dia = $arr[0];
    $mes = $arr[1];
    $ano = $arr[2];

    $ult = date("d", mktime(0,0,0,$mes+1,0,$ano));
    $dse = date("w", mktime(0,0,0,$mes,1,$ano));

    $tot = $ult+$dse;
    if($tot != 0){
      $tot = $tot+7-($tot%7);
    }

    for($i=0;$i<$tot;$i++){
      $dat = $i-$dse+1;
      if(($i >= $dse) AND ($i < ($dse+$ult))){
        $aux[$i]  = '
          <td ';

        if(($dat == date(d)) AND ($mes == date(m)) AND ($ano == date(Y))){
          $aux[$i] .= 'class="calendario_dias_hoje"';
        } else {
          $aux[$i] .= 'class="calendario_dias"';
        }

        if(($dat == date(d)) AND ($mes == date(m)) AND ($ano == date(Y))){
          $aux[$i] .= 'class="calendario_links_hoje"';
        } else {
          $aux[$i] .= 'class="calendario_links"';
        }
        
        $aux[$i] .= '><a href="calendario.php?data='.sprintf("%02.0f",$dat).'/'.$mes.'/'.$ano.'">'.$dat.'</a>
          </td>
        ';
      } else {
        $aux[$i] = '
          <td>
          </td>
        ';
    }

    if(($i%7) == 0){
      $aux[$i] = '<tr align="center">'.$aux[$i];
    }

    if(($i%7) == 6){
      $aux[$i] .= '</tr>';
    }
  }

  echo '
  <table cellspacing="0" cellpadding="0" class="calendario_tabela">
    <tr>
      <td>
        <table cellspacing="1" cellpadding="1">
          <tr class="calendario_mes_ano">
            <td>
  ';
  $this->mes_anterior($dia,$mes,$ano);
  echo '
            </td>
            <td colspan="5">'.$this->mes[$mes].'</td>
            <td>
  ';
  $this->mes_proximo($dia,$mes,$ano);
  echo '
</td>
          </tr>

          <tr class="calendario_mes_ano">
            <td>
  ';
  $this->ano_anterior($dia,$mes,$ano);
  echo '
            </td>
            <td colspan="5">'.$ano.'</td>
            <td>
  ';
  $this->ano_proximo($dia,$mes,$ano);
  echo '
            </td>
          </tr>

          <tr class="calendario_semana">
            <td WIDTH="30">D</td>
            <td WIDTH="30">S</td>
            <td WIDTH="30">T</td>
            <td WIDTH="30">Q</td>
            <td WIDTH="30">Q</td>
            <td WIDTH="30">S</td>
            <td WIDTH="30">S</td>
          </tr>
  ';
  echo implode(' ',$aux);
  if(count($aux) == 35){
    echo '
          <tr>
            <td colspan="7">&nbsp;</td>
          </tr>
    ';
  };
  echo '
          <tr>
            <td class="calendario_mes_ano" colspan="7" align="center">[ <a href="calendario.php?data='.date(d).'/'.date(m).'/'.date(Y).'">Hoje</a> ]</td>
          </tr>
        </table>
      </td>
    </tr>
  </table>
  ';
   } 
} 

$teste = new calendario;
$teste->cria($_GET["data"]);
?>