A userscript to add fields to the Watch Live section of Blaseball to calculate net winnings
Download a userscript manager for your browser, such as Tampermonkey. Add the blaseball-net-winnings-userscript.js file to the manager and refresh your Blaseball page.
Create a new bookmark in your browser, with the URL set to the contents of blaseball-net-winnings-bookmarklet.js. Open the bookmarklet while on the Watch Live tab to run the code.