diff --git a/lib/nulib/python/nulib/web/bootstrap.py b/lib/nulib/python/nulib/web/bootstrap.py
index ffba723..214c9d9 100644
--- a/lib/nulib/python/nulib/web/bootstrap.py
+++ b/lib/nulib/python/nulib/web/bootstrap.py
@@ -43,6 +43,13 @@ def load(prefix=None, icons=True, charset="utf-8"):
     ])
     return u"\n".join(lines)
 
+def sa(value, kw, name, default=Undef):
+    """si value est indéfini, récupérer la valeur avec le nom court dans kw
+    """
+    if value is Undef and name is not None: value = kw.pop(name, Undef)
+    if value is Undef: value = default
+    return value
+
 ################################################################################
 # Menu
 
@@ -246,15 +253,24 @@ class Alert(object):
     action = None
     showtb = None
 
-    def __init__(self, msg=None, exc_info=Undef, type="error", closeable=False, escape=None, action=None, showtb=True, **kw):
-        self(msg, exc_info, type, closeable, escape, action, showtb, **kw)
+    def __init__(self, msg=None, exc_info=Undef, type=Undef, closeable=Undef, escape=Undef, action=None, showtb=True, **kw):
+        exc_info = sa(exc_info, kw, 'e')
+        if exc_info is Undef: exc_info = sys.exc_info()
+        if exc_info == (None, None, None): exc_info = None
+        type = sa(type, kw, 't', "error")
+        closeable = sa(closeable, kw, 'c', False)
+        escape = sa(escape, kw, 'x', None)
+
+        self.msg = msg
+        self.exc_info = exc_info
+        self.type = ALERT_TYPE_MAP.get(type, type)
+        self.closeable = closeable
+        self.escape = escape
+        self.action = action
+        self.showtb = showtb
 
     def __call__(self, msg=Undef, exc_info=Undef, type=Undef, closeable=Undef, escape=Undef, action=Undef, showtb=Undef, **kw):
-        if exc_info is Undef: exc_info = kw.pop('e', Undef)
-        if type is Undef: type = kw.pop('t', Undef)
-        if closeable is Undef: closeable = kw.pop('c', Undef)
-        if escape is Undef: escape = kw.pop('x', Undef)
-
+        exc_info = sa(exc_info, kw, 'e')
         if msg is Undef:
             # si on ne spécifie pas de message, alors prendre la valeur actuelle
             msg = self.msg
@@ -263,11 +279,11 @@ class Alert(object):
             # si on spécifie un message, alors prendre aussi l'exception courante
             if exc_info is Undef: exc_info = sys.exc_info()
             if exc_info == (None, None, None): exc_info = None
-        if type is Undef: type = self.type
-        if closeable is Undef: closeable = self.closeable
-        if escape is Undef: escape = self.escape
-        if action is Undef: action = self.action
-        if showtb is Undef: showtb = self.showtb
+        type = sa(type, kw, 't', self.type)
+        closeable = sa(closeable, kw, 'c', self.closeable)
+        escape = sa(escape, kw, 'x', self.escape)
+        action = sa(action, kw, None, self.action)
+        showtb = sa(showtb, kw, None, self.showtb)
 
         self.msg = msg
         self.exc_info = exc_info
@@ -279,11 +295,7 @@ class Alert(object):
         return self
 
     def render(self, msg=Undef, exc_info=Undef, type=Undef, closeable=Undef, escape=Undef, action=Undef, showtb=Undef, **kw):
-        if exc_info is Undef: exc_info = kw.pop('e', Undef)
-        if type is Undef: type = kw.pop('t', Undef)
-        if closeable is Undef: closeable = kw.pop('c', Undef)
-        if escape is Undef: escape = kw.pop('x', Undef)
-
+        exc_info = sa(exc_info, kw, 'e')
         if msg is Undef:
             # si on ne spécifie pas de message, alors prendre la valeur initiale
             msg = self.msg
@@ -291,11 +303,11 @@ class Alert(object):
         else:
             # si on spécifie un message, alors prendre aussi l'exception courante
             if exc_info is Undef: exc_info = sys.exc_info()
-        if type is Undef: type = self.type
-        if closeable is Undef: closeable = self.closeable
-        if escape is Undef: escape = self.escape
-        if action is Undef: action = self.action
-        if showtb is Undef: showtb = self.showtb
+        type = sa(type, kw, 't', self.type)
+        closeable = sa(closeable, kw, 'c', self.closeable)
+        escape = sa(escape, kw, 'x', self.escape)
+        action = sa(action, kw, None, self.action)
+        showtb = sa(showtb, kw, None, self.showtb)
 
         if callable(msg):
             # si msg est callable, par défaut ne pas mettre le résultat en