Update delay JS script to catch click events before the scripts are loaded.
Add the delay JS script to the page after the meta charset if it's present.
Remove the clear cache notice after using clear used CSS since it also clears the cache.
Prevent a possible error on WooCommerce product pages with delay JS enabled.
Prevent a possible PHP notice in some cases when using remove unused CSS.
3rd party compatibility:
Improve delay JS compatibility with a number of scripts.