Notebook: Widget Javascript not detected. It may not be installed or enabled properly.

[simonm3]

I have done "jupyter nbextension enable --py --sys-prefix widgetsnbextension"

restarted the notebook. restarted the computer. Still get the error message when I do:

import ipywidgets as w
w.Button()

windows 10

ipywidgets 6.0.0
jupyter 1.0.0
jupyter_client 5.0.1
jupyter_core 4.3.0

[rolweber]

Do you have widgetsnbextension installed? Have you checked the messages printed by Jupyter for more information?

[gerdm]

I have the same error on macOS Sierra:
ipywidgets 6.0.0
jupyter 1.0.0
jupyter_client 5.0.1
jupyter_core 4.3.0

I too, have also tried "jupyter nbextension enable --py --sys-prefix widgetsnbextension"

Enabling notebook extension jupyter-js-widgets/extension... - Validating: OK

[simonm3]

yes I have widgetsnbextension installed version 2.0.0.

there is a message from jupyter saying server_extensions is deprecated use nbserver_extensions. I changed the config file accordingly then jupyter would not start at all. So I deleted it and did
jupyter nbextension enable --py --sys-prefix widgetsnbextension
and this recreates the json file with server_extensions. But the widgets still don't work.

[gerdm]

I downgraded to widgetsnbextension==1.2.6. I am not sure how to fix the problem, but worked for me using this version.

[simonm3]

Downgrading did not work for me.

On 28 August 2017 at 20:10, Gerardo Durán Martín [e-mail]
wrote:

I downgraded to widgetsnbextension==1.2.6. I am not sure how to fix the
problem, but worked for me using this version.

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[rolweber]

@gerdm: ipywidgets 6.0.0 requires widgetsnbextension 2.0.0. Could it be that you have two different Python environments, like one with Python 2 running the notebook server, and another one with Python 3 running your notebook kernel? ipywidgets must be installed in the kernel environment, the matching widgetsnbextension in the notebook server environment.

[rolweber]

@simonm3: I thought the configuration would go into a notebook.json file. But in my hosted environment, the command line from the documentation wouldn't work anyway, for lack of permissions. So I always have to change configuration files directly.

Have you checked the installed version of notebook?

[habemus-papadum]

Hi -- I am having the same issues as well on Mac Sierra 10.12.6:
I installed via miniconda:
conda install jupyter_core notebook nbconvert ipykernel ipywidgets
It looks like conda properly installs and enables widgetsnbextension
(I did try manually running: jupyter nbextension enable --py --sys-prefix widgetsnbextension anyways, to no avail)

Below are my package versions. Any advice on what version I could pin to work around this would be appreciated. Thanks!

# packages in environment at /Users/nehal/.stack-notebook/conda:
#
appnope                   0.1.0                    py36_0  
asn1crypto                0.22.0                   py36_0  
bleach                    1.5.0                    py36_0  
cffi                      1.10.0                   py36_0  
conda                     4.3.27           py36hb556a21_0  
conda-env                 2.6.0                         0  
cryptography              1.8.1                    py36_0  
decorator                 4.1.2                    py36_0  
entrypoints               0.2.3                    py36_0  
html5lib                  0.999                    py36_0  
idna                      2.5                      py36_0  
ipykernel                 4.6.1                    py36_0  
ipython                   6.1.0                    py36_0  
ipython_genutils          0.2.0                    py36_0  
ipywidgets                6.0.0                    py36_0  
jedi                      0.10.2                   py36_2  
jinja2                    2.9.6                    py36_0  
jsonschema                2.6.0                    py36_0  
jupyter_client            5.1.0                    py36_0  
jupyter_core              4.3.0                    py36_0  
markupsafe                1.0                      py36_0  
mistune                   0.7.4                    py36_0  
nbconvert                 5.2.1                    py36_0  
nbformat                  4.4.0                    py36_0  
notebook                  5.0.0                    py36_0  
openssl                   1.0.2l                        0  
packaging                 16.8                     py36_0  
pandocfilters             1.4.2                    py36_0  
path.py                   10.3.1                   py36_0  
pexpect                   4.2.1                    py36_0  
pickleshare               0.7.4                    py36_0  
pip                       9.0.1                    py36_1  
prompt_toolkit            1.0.15                   py36_0  
ptyprocess                0.5.2                    py36_0  
pycosat                   0.6.2                    py36_0  
pycparser                 2.17                     py36_0  
pygments                  2.2.0                    py36_0  
pyopenssl                 17.0.0                   py36_0  
pyparsing                 2.1.4                    py36_0  
python                    3.6.1                         2  
python-dateutil           2.6.1                    py36_0  
pyzmq                     16.0.2                   py36_0  
readline                  6.2                           2  
requests                  2.14.2                   py36_0  
ruamel_yaml               0.11.14                  py36_1  
setuptools                27.2.0                   py36_0  
simplegeneric             0.8.1                    py36_1  
six                       1.10.0                   py36_0  
sqlite                    3.13.0                        0  
terminado                 0.6                      py36_0  
testpath                  0.3.1                    py36_0  
tk                        8.5.18                        0  
tornado                   4.5.2                    py36_0  
traitlets                 4.3.2                    py36_0  
wcwidth                   0.1.7                    py36_0  
wheel                     0.29.0                   py36_0  
widgetsnbextension        3.0.2                    py36_0  
xz                        5.2.2                         1  
yaml                      0.1.6                         0  
zlib                      1.2.8                         3  

[rolweber]

@habemus-papadum: You've got ipywidgets 6.0 and widgetsnbextension 3.0.
Try upgrading ipywidgets to 7.0, or downgrading widgetsnbextension to 2.0.

[habemus-papadum]

pinning widgetsnbextension=2 solved the issue for me. I guess ipywidgets 6.0 was pushed to anaconda cloud (or whatever it is called) with too lax constraints on widgetsnbextension. Thanks very much for the quick response and help!

[csbenz]

@habemus-papadum What do you mean by 'pinning'?

[habemus-papadum]

I mean explicitly specifying the package versions I want to install:
e.g. conda install --yes jupyter_core notebook nbconvert ipykernel ipywidgets=6.0 widgetsnbextension=2.0 (this is just a random invocation that worked a few months ago -- you should vet which versions you need and which packages you want to pin, and so forth)

[chikean]

@rolweber's suggestion of downgrading widgetsnbextension to 2.0 when using ipywidgets=6.0 resolved this issue for me too.