I am looking to build a graphical frontend for some python functionality.  Since I am very proficient in HTML/CSS/JS I decided I might check this out as a possibility. 

The main idea is to make it easier to explore data/variables, I am thinking of a datagrid for example.  I was also thinking of creating a GUI for things such as plotting with matplotlib (ie: Choose variable for X axis, choose variable for Y axis, pick a color from a dropdown, ...) in order to cut out some of the tediousness in exploring data with several variables. 

I would then probably use something like Node-webkit to make a desktop application out of it if possible (and if not, just keep it as a browser project, perhaps). 

Essentially what it would boil down to is kind of creating an IDE for python, specialized for data exploration/plotting and perhaps data manipulation. 

An example I found for a web-based python console is repl.it

However I have spent a fair amount of time looking for viable ways to go about this, since sending and receiving data from the python interpreter wouldn't be too hard, but it might get a bit harder for exploring variables or plotting data. 

So the question is: Are there any projects or libraries out there to facilitate this kind of functionality, or which provide a good starting point for interacting with Python through JavaScript?  Are there any pointers you guys can give me to make the experience for users as seamless as possible? 

Thanks!