Bandwidth is cheap.
There are very few audiences to whom a mathematical proof is more convincing than a screenshot. And those audiences probably don't care about you. But if you really want to do it, you're probably better off modifying a proxy than a browser.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.