function form_modifie_presentation(){
    var dessus = document.getElementById('js_contenu_presentation_dessus').innerHTML;
    var dessous = document.getElementById('js_contenu_presentation_dessous').innerHTML;
    var comm = document.getElementById('commentaire').innerHTML;

    monForm = document.createElement("form");
    monForm.setAttribute('action', 'index.php?m=presentation&a=valide_modif');
    monForm.setAttribute('ENCTYPE', 'multipart/form-data');
    monForm.setAttribute("method", "POST");
    monForm.setAttribute("name", "modif_presentation");
    monForm.setAttribute("id", "modif_presentation");

    var son;
    if(document.getElementById("son_actif")){
        son = "<input type='checkbox' name='son_des' id='son_des' /> D&eacute;sactiver le son";
    }else{
        son = "<input type='checkbox' name='son_act' id='son_act' /> Activer le son";
    }

    monForm.innerHTML =  "<div id='modalalertdiv_contenu_presentation' class='yui-skin-sam' ><center><br/><table class='text_left' >"+
    "<tr><td>Texte au-dessus de la vid&eacute;o : </td><td><textarea cols='50' rows='5' name='contenu_superieur_presentation' id='contenu_superieur_presentation' >"+dessus+"</textarea></td></tr>"+
    "<tr><td>Commentaire sous la vid&eacute;o : </td><td><textarea cols='50' rows='5' name='comm_presentation' id='comm_presentation' >"+comm+"</textarea></td></tr>"+
    "<tr><td>Texte sous la vid&eacute;o : </td><td><textarea cols='50' rows='5' name='contenu_inferieur_presentation' id='contenu_inferieur_presentation' >"+dessous+"</textarea></td></tr>"+
    "<tr><td>Remplacer la vid&eacute;o ou mettre une image : </td><td><input type='file' name='video_presentation' id='video_presentation' /> (vid&eacute;o au format .flv)</td></tr>"+
    "<tr><td></td><td>"+son +"</td></tr>"+
    "</table>"+
    "<br /><input type='button' name='Annuler' value='Annuler' onclick='modalwindow.hide();' /> " +
    "<input type='submit' name='Valider' id='Valider' value='Valider'  /></center></div>";
	
    document.getElementById("modalalertdiv").appendChild(monForm);
	
    var larg = (document.body.clientWidth) / 2-325;
    var haut = 10;//(window.innerHeight/2)-250;
    var h = 530;
    if(window.innerHeight == null){
        haut = 10;
        h=700;
    }
	
    modalwindow = dhtmlmodal.open('modal', 'div', 'modalalertdiv',
        "Modification de la page de pr\351sentation", "width=650px,height="+h+"px,left=" + larg
        + ",top=" + haut + ",resize=0,scrolling=1");

    var editorDessus = new YAHOO.widget.Editor('contenu_superieur_presentation', {
        toolbar: bar
    });
    editorDessus.render();
    var editorDessous = new YAHOO.widget.Editor('contenu_inferieur_presentation', {
        toolbar: bar
    });
    editorDessous.render();

    var editorComm = new YAHOO.widget.Editor('comm_presentation', {
        toolbar: bar
    });
    editorComm.render();

    YAHOO.util.Event.on('Valider', 'click', function() {
        //Put the HTML back into the text area
        editorDessus.saveHTML();
        //The var html will now have the contents of the textarea
        var dessus = editorDessus.get('element').value;

        editorDessous.saveHTML();
        var dessous = editorDessous.get('element').value;

        editorComm.saveHTML();
        var comm = editorComm.get('element').value;

        var xhr = getXhr();
        // On défini ce qu'on va faire quand on aura la réponse
        xhr.onreadystatechange = function(){
            // On ne fait quelque chose que si on a tout reçu et que le serveur est ok
            if(xhr.readyState == 4 && xhr.status == 200){

        }
        };
        
        var des = document.getElementById("son_des").value;
        var act = document.getElementById("son_act").value;
        var data = 'contenu_superieur_presentation='+dessus+'&contenu_inferieur_presentation='+dessous+'&comm_presentation='+comm+'&son_des='+des+'&son_act='+act;

        xhr.open("POST",'index.php?m=presentation&a=valide_modif',true);
        xhr.send(data);
    });
}