Sos programation

<tr><td><label for="Categorie">Categorie du produit:</label></td><td><input type="text" id="Categorie" name="Categorie" size="20" maxlength="20" /></td></tr>
   <tr><td><label for="Quantite">quantite du produit:</label></td><td><input type="text" id="Quantite" name="Quantite" size="20" maxlength="20" /></td></tr>
   <tr><td><label for="libell">type d'enregistrement:</label></td><td><select name="libell" id="libell"> 
   <option value="">Choisir la transaction</option>
   <option value="">EntreeStock</option>
   <option value="">SortieStock</option>
   
     <tr> </tr>       
    <tr><center><td><input type="submit" value="Enregistrer" name="buttonEnregistrer" />
   <input type="reset" value="Annuler" name="buttonAnnuler" /></td> </center>
   </tr>
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

if(empty($_POST['Numart']) 
     or empty($_POST['ID_Article'])
       or empty($_POST['Nom_Fournisseur'])
        or    empty($_POST['Categorie']) 
          or     empty($_POST['Quantite'])
   or empty($_POST['libell']) )
    {
 ?><SCRIPT LANGUAGE="JAVASCRIPT"> alert("Vous devez remplir les champs svp!"); </SCRIPT><?php
  echo '<meta http-equiv="refresh" content="0; URL=ajouts_article.php">';//redirection
}
else{
      $NumartS=$_POST['Numart'];
        $ID_ArticleS=$_POST['ID_Article'];
          $Nom_ArticleS=$_POST['Nom_Article'];
            $Nom_Fournisseur=$_POST['Nom_Fournisseur'];
            $CategorieS=$_POST['Categorie'];
             $QuantiteS=$_POST['Quantite'];
    $libell=$_POST['libell'];