Problemas con la fecha de nacimiento en php

[farra]

Codigo PHP:

Código PHP:

  <?php 
// valida fecha   
$Diar=$_POST['dia']; 
$Mesr=$_POST['mes']; 
$Anhor=$_POST['ano']; 
if(($_POST['dia'] != "") && ($_POST['mes'] != "") &&  ($_POST['ano'] != "")){ 
    if (checkdate($Mesr, $Diar, $Anhor)) { 
    $fechaValida=true; 
    } else { 
    $fechaValida=false; 
    $valido=false; 
    } 
} 
// valida fecha  
 
?>   

Codigo HTML:

Código HTML:

<style type="text/css">
<!--
.valido {
	color: #009900;
	font-weight: bold;
}
.novalido {
	color: #FF0000;
	font-weight: bold;
}
-->
</style>
  <form method="post" name="form1" action="PRUEBA.PHP">
<TABLE>
<tr valign="baseline">
                    <td nowrap align="right"><span >*</span>Fecha de Nacimiento:</td>
                    <td colspan="2" align="left"><select name="dia">
                        <option value="">dia</option>
                      <?php $Dias="1" ?>
                      <?php while($Dias <= "31"){ ?>
                      <option <?php if($Dias == $_POST['dia']){  ?>selected="selected"<?php }?> value="<?php echo $Dias; ?>"><?php echo $Dias; ?></option>
                      <?php $Dias=$Dias+1 ?>
                      <?php } ?>
                      </select>
                      <select name="mes">
					  <option value="">mes</option>
                        <option value="1" <?php if ($_POST['mes'] == "1"){  ?> selected="selected"<?php } ?> >Enero</option>
						<option value="2" <?php if ($_POST['mes'] == "2"){  ?> selected="selected"<?php } ?> >Febrero</option>
						<option value="3" <?php if ($_POST['mes'] == "3"){  ?> selected="selected"<?php } ?> >Marzo</option>
						<option value="4" <?php if ($_POST['mes'] == "4"){  ?> selected="selected"<?php } ?> >Abril</option>
						<option value="5" <?php if ($_POST['mes'] == "5"){  ?> selected="selected"<?php } ?> >Mayo</option>
						<option value="6" <?php if ($_POST['mes'] == "6"){  ?> selected="selected"<?php } ?> >Junio</option>
						<option value="7" <?php if ($_POST['mes'] == "7"){  ?> selected="selected"<?php } ?> >Julio</option>
						<option value="8" <?php if ($_POST['mes'] == "8"){  ?> selected="selected"<?php } ?> >Agosto</option>
						<option value="9" <?php if ($_POST['mes'] == "9"){  ?> selected="selected"<?php } ?> >Septiembre</option>
						<option value="10" <?php if ($_POST['mes'] == "10"){  ?> selected="selected"<?php } ?> >Octubre</option>
						<option value="11" <?php if ($_POST['mes'] == "11"){  ?> selected="selected"<?php } ?> >Noviembre</option>
						<option value="12" <?php if ($_POST['mes'] == "12"){  ?> selected="selected"<?php } ?> >Diciembre</option>
                      </select>
                      <select name="ano">
                        <option value="">ano</option>
<?php 
$hoyano=date("Y");
//$hoydateyear=$hoyano-18;
$hoydateyear=$hoyano-1;
$dateyear=$hoydateyear-100;
?>
                      <?php while($dateyear <= $hoydateyear){ ?>
                      <option <?php if ($dateyear == $_POST['ano']) {?>selected="selected" <?php }?> value="<?php echo $dateyear; ?>"><?php echo $dateyear; ?></option>
                      <?php $dateyear=$dateyear+1 ?>
                      <?php } ?>
                      </select><?PHP
if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form1")) {
	if($fechaValida){
		echo "<span class='valido'>La fecha es correcta</span>";
	}else{
		echo "<span class='novalido'>La fecha es incorrecta</span>";
	}
}
?></td>
                  </tr> <?php if (isset($_POST['MM_insert']) && ($_POST['ano']=="" or $_POST['ano']==" " or $_POST['mes']=="" or $_POST['mes']==" " or $_POST['dia']=="" or $_POST['dia']==" ")) { ?> <tr valign="baseline">
                    <td align="center" nowrap="nowrap" >&nbsp;</td>
                    <td align="left" nowrap="nowrap" >*Debe completar este campo </td>
                    <td align="center" nowrap="nowrap" >&nbsp;</td>
                  </tr><?php } ?></TABLE> <input type="hidden" name="MM_insert" value="form1">
</form>