Library for html5 slider in firefox uses a soon to be deprecated function

[imbstack]

The library should be updated or check to see if Firefox will natively support the range element before the Mutation Event is deprecated.

[01:36:53.373] Use of Mutation Events is deprecated. Use MutationObserver instead. @ http://localhost:8889/static/vendor/html5slider.js?v=d17ec:75