Describe the bug
Widget embed seems to only intermittently work. The issue seems to fire less frequently in Safari, but seems to be consistent with Chrome and Firefox - possibly a race condition.

An error is presented in the console:
hook.js:608 HiEvent widget error: Invalid script URL

To Reproduce
Steps to reproduce the behavior:

1. embed the script in the tags: <script async src="https://someexternaldomain.com/widget.js"></script> (note that the hi.events domain is different to the domain where the widget is embedded)
2. Embed a widget into the page
3. Loading the page intermittently throws the error. I had some luck re-producing more often the embed website being in http://.

Additional context
widget.js uses document.currentScript in order to retrieve the current hostname. I believe this is not always reliable in every browser or scenario. PR incoming.