TLDR; You have to start the http server (simple-http) and load your HTML files through it.
<!-- Include skewer.js as a script -->
Instead of running the demo, just perform these minimal steps to ensure that everything is working correctly.
Open a new buffer with the name myskewer.js
Enable JS2-mode (a dependency of skewer)
M-xrun-skewer (a browser opens, go back to myskewer.js)
Type alert("hello"); and hit C-xC-e at the end of that line
Go back to the browser.
Finally figured this out. Make sure that the following line is present in the greasemonkey script which you inject:
// @include /^https?:///
That will enable skewering of every site. Now do a refresh of the the
page. Now at the top right hand side of the window (firefox window)
there will be a red triangle. Press on that triangle to inject the