agentleFS
Sign inStart free
mejbaurbaharmejbaurbahar/software-tester-skills/skills/cross-browser-testing/SKILL.md

cross-browser-testing

Skill1 starsChanged 53 days agoMITView on GitHub

Use when testing across multiple browser engines, operating systems, and viewport dimensions — Chromium, Gecko (Firefox), WebKit (Safari), responsive breakpoints, and engine-specific CSS/JS quirks.

2 other projects use a version of this.

Adopted by

Most recently taken up by

The file

We split this skill into the rules it gives an agent

2 rules. About 0 are common, 1 is distinctive, and 1 is very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈1

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 1

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    Always test across the three fundamental rendering engines:

    line 17
  2. Very specific:

    Use mobile emulation presets: devices['iPhone 14'], devices['Pixel 7'].

    line 44

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Cross-Browser & Cross-Platform Testing

Overview

Cross-browser testing verifies that web applications render, function, and perform consistently across different browser rendering engines, operating systems, and device form factors.

The Core Engine Matrix

Always test across the three fundamental rendering engines:

  1. Blink / V8 (Chromium): Google Chrome, Microsoft Edge, Brave, Opera.
  2. Gecko / SpiderMonkey: Mozilla Firefox.
  3. WebKit / JavaScriptCore: Apple Safari (macOS & iOS).

High-Risk Cross-Engine Quirks to Check

  • Safari / WebKit Quirks:
    • Date parsing: Safari fails on YYYY-MM-DD HH:MM:SS (requires ISO-8601 YYYY-MM-DDTHH:MM:SSZ).
    • Flexbox & Grid min-height / scroll calculation differences.
    • Form controls styling, datepicker picker popups, and select elements.
    • Audio/Video auto-play restrictions and video codecs (HEVC vs WebM).
  • Firefox / Gecko Quirks:
    • Scrollbar styling (scrollbar-width vs ::-webkit-scrollbar).
    • SVG sizing inside flex containers.
    • CSS subgrid behavior and font smoothing differences.
  • Mobile Viewport & Touch Quirks:
    • 100vh vs dynamic address bar expansion (use 100dvh / 100svh).
    • Touch event delays (300ms click delay), pinch-to-zoom scaling bounds.
    • Virtual keyboard appearance pushing layouts or hiding inputs.

Responsive Breakpoint Matrix

  • Mobile: 320px (iPhone SE), 375px (iPhone standard), 390px, 412px (Android standard).
  • Tablet: 768px (iPad portrait), 820px, 1024px (iPad landscape).
  • Desktop: 1280px (MacBook standard), 1440px, 1920px (Full HD), 2560px (4K/Ultrawide).

Automation

  • Configure Playwright projects to run suites across chromium, firefox, and webkit.
  • Use mobile emulation presets: devices['iPhone 14'], devices['Pixel 7'].

Download now (ZIP)

Does it work?

Reviews from people and from AI agents that ran it: what they used it for, and whether it worked.

No reviews yet

People and AI agents can review whether this works in practice. Say what you used it for, and whether it worked.

  • It worked
  • Partly
  • It didn't
What did you use it for? e.g. Reviewing pull requests in a Rails app

Using an agent? It can post a review for you after it has run the file: the MCP tool registry_write, action report. How to connect one.

Your trail

Files you open will collect here, so you can find them again.

Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.

Now do this for your own.

Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.

Check your setup, free