Mon bouton submit ne marche pas

                    <form name="actu_form" id="uploadimage"  enctype="multipart/form-data" class="formulaire" style="margin:0px;padding:0px;" method="POST" action="<?php echo $UP;?>administration/includes/incfiles/allajax.inc.php">
                        <div id="image_preview">
                            <img id="previewing" src="<?php echo $UP;?>images/aucune_image_disponible.png" title="cliquer sur joindre pour ajouter une image" alt="aucune_image_disponible" style="width: 150px; height:80px; padding:5px; float:left;" />
                        </div>
                        <div id="selectImage" style="">
                            <div id="img">
                                <span name="JFile" data-inputfilename="file" style="cursor:pointer;"><a><img src="<?php echo $UP;?>images/input.png" title=""></a></span>
                                    <input type="file" name="file" id="file" style="display:none;" required />
                            </div>
                        </div></br></br></br></br></br></br>
                        <table>
                            <tr>
                                <td style="font-weight:bold;">Titre de l'information</td>
                                <td><input required type="text" name="titre" value="<?php if(isset($_POST['titre'])){echo htmlentities($_POST['titre'], ENT_QUOTES, 'UTF-8');} ?>" style="font-weight:bold; width:580px; min-width:580px; max-width:580px; "></td>
                            </tr>
                            <tr>
                                <td></td>
                                <td><b>Texte/Contenu de l'information</b><textarea name="contenu" value="<?php if(isset($_POST['titre'])){echo htmlentities($_POST['titre'], ENT_QUOTES, 'UTF-8');} ?>" style="text-align:justify; margin:5px; padding:5px; width:580px; max-width:580px; height:400px; max-height:400px;"></textarea></td>
                            </tr>
                            <tr>
                                <td>
                                    <button class="submit tp14 b" type="submit" name="ecole" style="width:auto; margin:5px; padding:5px; margin-bottom:10px;">
                                            Sauvegarder
                                    </button>
                                </td>
                            </tr>
                        </table>

                    </form>