Kernel js

Some Jupyter kernels might need to load custom javascript on the page. If you decide to do so, then the unloading of this javascript is not guaranteed and if your user wants to switch back to another kernel they will most likely need to refresh the page.

We might even enforce the reloading of the page for kernels shipping with custom JavaScript.

Though, if you like to ship JavaScript with your kernel(s) and have it loaded when the user switches to your kernel or opens a notebook working with your kernel, then you need to put a kernel.js file in the kernelspec folder of your kernel.

It is recommended for this file to define an anonymous module that exposes (at least) the onload method which takes no arguments.

Here is a minimal version of such a file:


    var onload = function(){
        console.log("I am being loaded")    

    return {onload:onload}

You will notice the presence of define() instead of require() used in previous custom.js. This example does not have any dependencies but you can express them as in any other extensions.

The onload method will be called by Jupyter/IPython at the right time