To use the SSL compliant timplot (https://) and to avoid MIME errors use the following url in the JS include:
https://cdn.rawgit.com/smachaje/timeplot/master/simile/1.1/src/webapp/api/timeplot-api.js
like this:
<script src="https://cdn.rawgit.com/smachaje/timeplot/master/simile/1.1/src/webapp/api/timeplot-api.js" type="text/javascript"></script>