No output when using webagg backend

Community matplotlib-users
1

I'm trying to use the webagg backend for the first time, and seem to
be bumping into a common problem - nothing appears. The first time I
tried, I got a complaint that tornado was missing, so I installed it.
After that, I get to try plotting. Here's my example:

import matplotlib
matplotlib.use('webagg')
import matplotlib.pyplot as plt
plt.plot(range(10))

[<matplotlib.lines.Line2D object at 0x2f56690>]

plt.show()

Created new window in existing browser session.
Press Ctrl+C to stop server
^CServer stopped

When I execute plt.show(), a new tab opens in my browser (Chrome, on
Linux) with this URL: http://127.0.0.1:8988. That page has a single
link (text: "Figure 1"). If I click that link, I get this URL:
http://127.0.0.1:8988/1, but nothing appears. The page source contains
a bunch of JavaScript references. For instance:

<script src="/_static/jquery/js/jquery-1.7.1.min.js"></script>
<script src="/_static/jquery/js/jquery-ui.min.js"></script>
<script src="/_static/mpl.js"></script>
<script src="/1/mpl_interface.js"></script>

I see those JavaScript files at appropriate places in the
.../backends/web_backend directory. What am I missing?

Thx,

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2

I'm trying to use the webagg backend for the first time, and seem to
be bumping into a common problem - nothing appears.

I tried this at home on my Mac. Tornado was already installed, so I
updated it to 3.2.1, and ran a Matplotlib app I have which allows me
to set the backend on the command line. I get the exact same behavior
as at work on my Linux desktop. I get a page at 127.0.0:8988 with a
"Figure 1" link. Clicking that takes me to 127.0.0.1:8988/1, which is
a blank page.

Chrome is my default web browser on both Linux and the Mac. I manually
visited the page from both Firefox and Safari, clicked the link,
and... nothing. The same behavior as on Chrome.

Then I had the bright idea to look at the JavaScript console. It shows
this error message:

  Uncaught SyntaxError: Unexpected token &

Clicking that error took me to this line:

var fig = new figure(&#39;1&#39;, websocket_url_prefix);

Are those entities supposed to be ''? What bit of code generates that
JavaScript?

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