Safari has a new feature called "Content Blockers" that allows for extremely efficient resource blocking on both the desktop and iOS version of Safari. As much as I'd like to incorporate this into JS Blocker, it is not feasible to do so. Using a content blocker will prevent JS Blocker from showing you exactly what's going on on a website (i.e. you won't see what's allowed or blocked.) It'll also break all of JS Blocker's "other" features, such as showing alerts within the webpage and canvas fingerprinting protection. Besides the loss of features, content blockers are limited to 50,000 rules. While this seems like a high number, it isn't enough for efficient protection and a lot of rules would need to be cut out to even run a content blocker. Until Apple eases the restrictions (or at least raises the number of rules that can be in a content blocker), JS Blocker will not be using this API.