function ecrire_pseudo(str_pseudo) {
var inputmessage = document.getElementById("message");
inputmessage.value = 'a ' + str_pseudo + ': ';
inputmessage.focus();
<!--alert(str_pseudo);-->
} 
$(function() {
var ini_id_chat = $('#chat select[name=chats]').val();

    $('#chat form').submit(function() {
        var id_chat = $('#chat select[name=chats]').val();
        var user    = $('#chat input[name=user]').val();
        var message = $('#chat input[name=message]').val(); 
            
        if (user == '' || user == 'Administrateur') {
        alert('Login vide ou interdit');
        return false;
        } 
        if (user == 'Anonyme'){
        alert('Choisissez un pseudo Anonyme interdit');
        return false;
        }
                if (message == '') {
        alert('Message vide!');
        return false;
        }
        $.post('/include/js/ajax/chat.php', { 'id_chat': id_chat, 'user':user, 'message':message }, function() {
            refreshChat(id_chat);
        });
        $('#chat input[name=message]').val('');
        return false;
    });

    $('#chat form #chats').change(function() {
      var id_chat = $('#chat select[name=chats]').val();
      refreshChat(id_chat);
    });
    
    $('#room').mouseover(function(){
      clearTimeout(timer);
      timer = setTimeout(refreshChattimer, 10000); 
    });  

    function refreshChat(id_chat) {
                $.ajax({
            url: "/include/js/ajax/chat.php?lire=1&&id_chat="+id_chat, 
            success: function(content){
                $('#room').html(content);
            }
        });
        
        var objDiv = document.getElementById("room");
<!--objDiv.scrollTop = objDiv.scrollHeight;-->
       
        timer = setTimeout(refreshChattimer, 5000);            
    }
        
    function refreshChattimer() {
        var id_chat = $('#chat select[name=chats]').val(); 
        refreshChat(id_chat);
    }

    refreshChat(ini_id_chat);
});