Quick answer: Test on the major browsers your players use, since each has different WebGL behavior, with Safari especially worth checking, and capture crashes and errors tagged by browser from real players.
For a WebGL game, different browsers are effectively different platforms, with different WebGL implementations and quirks, so a game that works in one can break in another. Testing across them is essential. Here's how to test your WebGL game across browsers.
Test the Major Browsers
Browsers behave like distinct platforms for a WebGL game, Chrome, Firefox, and Safari have different WebGL implementations, JavaScript performance, and edge-case handling. Test your game on the major browsers your players use, since each can reveal issues the others don't, and a game that's perfect in one may break in another.
You can't test every browser and version, but covering the major ones catches most issues. Safari in particular often has WebGL quirks worth checking specifically. Manual testing across these browsers catches many browser-specific problems before players hit them.
Capture Issues Tagged by Browser
Manual testing can't cover every browser, version, and configuration, so back it with field capture. Crashes and errors tagged by browser from real players reveal the browser-specific problems your testing missed, the Safari rendering glitch, the Firefox performance issue, on configurations you didn't test.
Bugnet captures errors and crashes tagged by browser from real sessions, so cross-browser issues surface even on browsers you couldn't test. For a WebGL game, the browser context is as important as the stack trace, it's what identifies a problem as browser-specific.
Prioritize by Which Browsers Players Use
You don't have infinite testing time, so prioritize by your actual audience: which browsers your players use most. Field data showing your browser distribution tells you where to focus testing and which browser-specific issues affect the most players, so your effort goes where it matters.
Bugnet's browser-tagged data shows which browsers your players use and where issues concentrate, so you prioritize testing and fixes by real impact. Testing your WebGL game across browsers is covering the major ones manually, capturing browser-tagged issues from the field, and prioritizing by your audience, which together handle browser diversity efficiently.
Test the major browsers (Safari especially), since each has different WebGL behavior, and capture crashes tagged by browser from real players. Browsers are effectively different platforms, so cover them and use field data.