Form:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Cadastrar Associado</title>
<style type="text/css">
</head>
<body>
<table width="625" border="0" align="center">
<tr>
<td width="69">
<fieldset>
<legend><font size="3" face="verdana"><strong>Cadastro de Associado</strong></font> </legend>
<span class="style1"><font size="1" face="verdana"><b>Todos os campos são obrigatórios!</b></font></span><br><br>
<form id="cadastro" name="cadastro" method="post" action="grava_matricula_mensalidade.php">
<font size="2" face="verdana"><b>
<table width="625" border="0">
<tr>
<td width="69">Matrícula:</td>
<td width="546"><input name="matricula" type="text" id="matricula" size="4" maxlength="4" /></span></td>
</tr>
<tr>
<td colspan="2"><p>
<br>
<input name="cadastrar" type="submit" id="cadastrar" value="Cadastrar" />
<br><br>
</td>
</tr>
</table>
</font></b>
</form>
</fieldset>
</td>
</tr>
</table>
</body>
</html>
grava_matricula_mensalidade.php:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<body>
<?php
$matricula = $_POST['matricula'];
$conexao1 = mysql_connect("localhost","root","123");
if (!$conexao1)
die ("Erro de conexão com localhost, o seguinte erro ocorreu -> ".mysql_error());
$banco = mysql_select_db("coloniaam34",$conexao1);
if (!$banco)
die ("Erro de conexão com banco de dados, o seguinte erro ocorreu -> ".mysql_error());
$query = ("INSERT INTO mensal_anual (matricula) VALUE ('$matricula')");
mysql_query($query,$conexao1);
echo "Seu cadastro foi realizado com sucesso!<br>Agradecemos a atenção.";
?>
<p>
<meta HTTP-EQUIV="Refresh" CONTENT="0; URL=cadastrar_matricula.html">
</body>
</html>
NOTE: It says that you registered correctly, but not saved in BD mysql.
Would anyone know the error?