It's available for Chrome, Microsoft Edge, Safari, Opera Next, and Firefox. It allows its users to customize and enhance the functionality of your favorite web ...
It's UI is very unintuitive but I still kept using it for many months daily, it did its job. However, then I encountered a deal-breaking bug, it seems:
2017年11月15日 — How to Transfer All Greasemonkey userscripts to Tampermonkey on Firefox 57+ ... Userscript works in Tampermonkey on Chrome but not in Greasemonkey ...