diff --git a/META.js_of_ocaml.template b/META.js_of_ocaml.template
index 2b2ba824d5..86e5b0901c 100644
--- a/META.js_of_ocaml.template
+++ b/META.js_of_ocaml.template
@@ -24,6 +24,10 @@ package "graphics" (
   requires = "js_of_ocaml-lwt.graphics"
 )
 
+package "log" (
+  requires = "js_of_ocaml-lwt.logger"
+)
+
 package "ocamlbuild" (
   requires = "js_of_ocaml-ocamlbuild"
 )
diff --git a/doc/Makefile b/doc/Makefile
index 61ba945803..8703c6b13d 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -10,8 +10,8 @@ MLIS+=$(wildcard ${SRC_DIR}ocamlbuild/*.mli)
 OTHER+=-I ${CMI_DIR}lib  -package ocamlbuild -I ${CMI_DIR}ocamlbuild -I ../_build/install/default/lib/js_of_ocaml -I ../_build/install/default/lib/js_of_ocaml/deriving -I ../_build/install/default/lib/js_of_ocaml-tyxml
 
 ifeq "${WITH_LWT}" "YES"
-OTHER += -package lwt -I ${CMI_DIR}lib/lwt
-MLIS+=$(wildcard ${SRC_DIR}lib/lwt/*.mli)
+OTHER += -package lwt -I ${CMI_DIR}lib/lwt -I ${CMI_DIR}lib/lwt/log
+MLIS+=$(wildcard ${SRC_DIR}lib/lwt/*.mli) $(wildcard ${SRC_DIR}lib/lwt/log/*.mli)
 ifeq "${WITH_GRAPHICS}" "YES"
 OTHER+=-package graphics -I ${CMI_DIR}lib/lwt/graphics
 MLIS+=$(wildcard ${SRC_DIR}lib/lwt/graphics/*.mli)
diff --git a/doc/api/index b/doc/api/index
index 576bba98f8..dea55726e9 100644
--- a/doc/api/index
+++ b/doc/api/index
@@ -38,6 +38,12 @@ Lwt_js_events
 Lwt_js
 }
 
+{2 Lwt logger - API Reference}
+
+{!modules:
+Lwt_log_js
+}
+
 {2 Graphics - API Reference}
 
 {!modules:
diff --git a/lib/lwt/log/jbuild b/lib/lwt/log/jbuild
new file mode 100644
index 0000000000..a23e2926bc
--- /dev/null
+++ b/lib/lwt/log/jbuild
@@ -0,0 +1,8 @@
+(jbuild_version 1)
+(library
+ ((name lwt_log_js)
+  (public_name js_of_ocaml-lwt.logger)
+  (synopsis "Lwt logger for js_of_ocaml.")
+  (optional)
+  (libraries (js_of_ocaml lwt lwt.log))
+  (preprocess (pps (js_of_ocaml-ppx)))))
diff --git a/lib/lwt/log/lwt_log_js.ml b/lib/lwt/log/lwt_log_js.ml
new file mode 100644
index 0000000000..b66803f48a
--- /dev/null
+++ b/lib/lwt/log/lwt_log_js.ml
@@ -0,0 +1,99 @@
+(* Js_of_ocaml library
+ * http://www.ocsigen.org/js_of_ocaml/
+ * Copyright (C) 2014 Hugo Heuzard
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, with linking exception;
+ * either version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *)
+
+include Lwt_log_core
+open Js_of_ocaml
+let js_val = Lwt.new_key ()
+
+let console = make
+    ~close:(fun _ -> Lwt.return_unit)
+    ~output:(fun section level logs ->
+        let str =
+          (Js.string
+             (Printf.sprintf "[%s] %s" (Section.name section) (String.concat "\n" logs)))
+        in
+        (match level,Lwt.get js_val with
+         | Debug,None -> Firebug.console##debug str
+         | Debug,Some v -> Firebug.console##debug_2 str v
+
+         | Info,None
+         | Notice,None ->  Firebug.console##info str
+         | Info,Some v
+         | Notice,Some v ->  Firebug.console##info_2 str v
+
+         | Warning,None -> Firebug.console##warn str
+         | Warning,Some v -> Firebug.console##warn_2 str v
+
+         | Error,None
+         | Fatal,None ->   Firebug.console##error str
+         | Error,Some v
+         | Fatal,Some v ->   Firebug.console##error_2 str v
+        );
+        Lwt.return_unit
+      )
+
+let log ?inspect ?exn ?section ?location ?logger ~level message =
+  let inspect = match inspect with None -> None | Some v -> Some (Obj.repr v) in
+  Lwt.with_value js_val inspect (fun () ->
+      log ?exn ?section ?location ?logger ~level message
+    )
+let log_f ?inspect ?exn ?section ?location ?logger ~level format =
+  Printf.ksprintf (log ?inspect ?exn ?section ?location ?logger ~level) format
+
+let ign_log ?inspect ?exn ?section ?location ?logger ~level message =
+  try
+    ignore (log ?inspect ?exn ?section ?location ?logger ~level message)
+  with _ ->
+    ()
+
+let ign_log_f ?inspect ?exn ?section ?location ?logger ~level format =
+  Printf.ksprintf (ign_log ?inspect ?exn ?section ?location ?logger ~level) format
+
+let debug ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Debug msg
+let debug_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (debug ?inspect ?exn ?section ?location ?logger) fmt
+let info ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Info msg
+let info_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (info ?inspect ?exn ?section ?location ?logger) fmt
+let notice ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Notice msg
+let notice_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (notice ?inspect ?exn ?section ?location ?logger) fmt
+let warning ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Warning msg
+let warning_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (warning ?inspect ?exn ?section ?location ?logger) fmt
+let error ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Error msg
+let error_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (error ?inspect ?exn ?section ?location ?logger) fmt
+let fatal ?inspect ?exn ?section ?location ?logger msg = log ?inspect ?exn ?section ?location ?logger ~level:Fatal msg
+let fatal_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (fatal ?inspect ?exn ?section ?location ?logger) fmt
+
+let ign_debug ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Debug msg
+let ign_debug_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_debug ?inspect ?exn ?section ?location ?logger) fmt
+let ign_info ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Info msg
+let ign_info_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_info ?inspect ?exn ?section ?location ?logger) fmt
+let ign_notice ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Notice msg
+let ign_notice_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_notice ?inspect ?exn ?section ?location ?logger) fmt
+let ign_warning ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Warning msg
+let ign_warning_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_warning ?inspect ?exn ?section ?location ?logger) fmt
+let ign_error ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Error msg
+let ign_error_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_error ?inspect ?exn ?section ?location ?logger) fmt
+let ign_fatal ?inspect ?exn ?section ?location ?logger msg = ign_log ?inspect ?exn ?section ?location ?logger ~level:Fatal msg
+let ign_fatal_f ?inspect ?exn ?section ?location ?logger fmt = Printf.ksprintf (ign_fatal ?inspect ?exn ?section ?location ?logger) fmt
+
+
+(*let raise_error ?inspect ?exn ?section ?location ?logger msg =
+  Lwt.ignore_result (log ?inspect ?exn ?section ?location ?logger ~level:Error msg);
+  failwith msg *)
+(*let raise_error_f ?inspect ?exn ?section ?location ?logger fmt =
+  Printf.ksprintf (raise_error ?inspect ?exn ?section ?location ?logger) fmt *)
diff --git a/lib/lwt/log/lwt_log_js.mli b/lib/lwt/log/lwt_log_js.mli
new file mode 100644
index 0000000000..d6d65a118e
--- /dev/null
+++ b/lib/lwt/log/lwt_log_js.mli
@@ -0,0 +1,98 @@
+(* Js_of_ocaml library
+ * http://www.ocsigen.org/js_of_ocaml/
+ * Copyright (C) 2014 Hugo Heuzard
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, with linking exception;
+ * either version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *)
+
+
+include module type of Lwt_log_core
+  with type level = Lwt_log_core.level
+   and type logger = Lwt_log_core.logger
+   and type section = Lwt_log_core.section
+   and type template = Lwt_log_core.template
+   and module Section = Lwt_log_core.Section
+
+(** Lwt logger for js_of_ocaml *)
+
+(** {2 Predefined logger} *)
+
+val console : Lwt_log.logger
+(** Logger that use the javascript console object. *)
+
+
+(** {2 Logging functions} *)
+
+val log : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> level : level -> string -> unit Lwt.t
+  (** [log ?section ?logger ~level message] logs a message.
+
+      [section] defaults to {!Section.main}. If [logger] is not
+      specified, then the default one is used instead (see
+      {!default}).
+
+      If [exn] is provided, then its string representation
+      (= [Printexc.to_string exn]) will be append to the message, and if
+      possible the backtrace will also be logged.
+
+      If [inspect] is provided, it will be append to the message.
+
+      [location] contains the location of the logging directive, it is
+      of the form [(file_name, line, column)]. *)
+
+val log_f : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> level : level -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+  (** [log_f] is the same as [log] except that it takes a format
+      string *)
+
+val ign_log : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> level : level -> string -> unit
+  (** Same as {!log} but ignore the resulting thread. *)
+
+val ign_log_f : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> level : level -> ('a, unit, string, unit) format4 -> 'a
+  (** Same as {!log_f} but ignore the resulting thread. *)
+
+(** The following functions are the same as {!log} except that their
+    name determines which level is used.
+
+    For example {!info msg} is the same as {!log ~level:Info msg}.
+*)
+
+val debug : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val debug_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_debug : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_debug_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a
+
+val info : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val info_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_info : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_info_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a
+
+val notice : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val notice_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_notice : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_notice_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a
+
+val warning : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val warning_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_warning : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_warning_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a
+
+val error : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val error_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_error : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_error_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a
+
+val fatal : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit Lwt.t
+val fatal_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit Lwt.t) format4 -> 'a
+val ign_fatal : ?inspect : 'v -> ?exn : exn -> ?section : section -> ?location : (string * int * int) -> ?logger : logger -> string -> unit
+val ign_fatal_f : ?inspect : 'v -> ?exn : exn ->  ?section : section -> ?location : (string * int * int) -> ?logger : logger -> ('a, unit, string, unit) format4 -> 'a