TypeError: null is not an object - document.getElementsByTagName

[maggie44]

When using the reader in Safari, the following message is logged in the console:

TypeError: null is not an object (evaluating '(document.body||document.getElementsByTagName("head")[0]).lastChild.src')

You can replicate this by viewing the demo epubjs reader in Safari and changing a page: https://futurepress.github.io/epubjs-reader/#epubcfi(/6/8[xpreface_001]!/4/2/2/2/1:0)

I haven't been able to replicate the issue in FireFox.

I have also experienced this in my own implementation of the reader (not using the demo site), but using the demo site as an easy way to replicate the issue.