For anyone involved with web development, compatibility across browsers is the bane of our existence. I still have nightmares about struggling with CSS working perfectly in Chrome but breaking horribly in Safari and Firefox. Even with standards convergence across modern browsers, we still run into subtle browser differences that can severely impact user experiences.
Why Cross Browser Testing Matters More Than Ever
Let‘s start with some context on why we can‘t ignore cross browser testing, even in 2024:
Browser Market Share Still Fragmented
While Chrome leads desktop browsing with 65% market share, Safari (15.4%), Firefox (8.2%) and Edge (4.5%) still represent hundreds of millions of users globally. On mobile, the split is even wider with Safari absolutely dominating on iOS and a mix of Chromium, Samsung Internet and others on Android devices.
| Browser | Global Desktop Market Share |
|---|---|
| Chrome | 64.34% |
| Safari | 15.40% |
| Firefox | 8.17% |
| Edge | 4.50% |
Source: StatCounter GlobalStats
Business Impact of Browser Bugs
According to Forrester Research, over $3 billion in online sales are lost every year in the US alone due to browser compatibility issues leading to broken sites. But it goes beyond ecommerce – from user acquisition to brand reputation, browser bugs significantly hurt key business metrics.
Frustrating User Experiences
Even minor visual glitches can confuse and frustrate users. For example text getting cutoff on Firefox, images not loading properly on Safari or unusable sites on old Android WebViews. Users blame the site, not understanding underlying browser causes. This erodes user trust regardless of fault.
Simply put, we cannot ignore how radically sites can break across browsers. Performing automated cross browser testing needs to be a fundamental part of our development practice, right from the start through post-launch. End users should not be quality assurance – we need to verify experiences proactively.
This is where browser test automation frameworks like Puppeteer come in very handy…
Configuring Puppeteer‘s Cross Browser Superpowers
As mentioned upfront, Puppeteer supports driving the three major browsers – Chrome/Chromium, Firefox and Edge. However, we need to configure tests appropriately depending on target browser and testing environment.
Let‘s walk through key setup steps:
Launching Different Browsers
// Launch latest Chromium/Chrome
await puppeteer.launch()
// Launch Firefox Nightly
await puppeteer.launch({
product: ‘firefox‘,
extraPrefsFirefox: {
‘devtools.chrome.enabled‘: true
}
})
// Launch Headful Edge Beta on Windows
await puppeteer.launch({
executablePath: ‘C:\\Program Files (x86)\\Microsoft\\Edge Beta\\Application\\msedge.exe‘,
headless: false
})Headless vs Headful Mode
By default, Puppeteer launches in headless mode without a visible UI. For debugging, switch to headful mode using the headless: false option.
Specifying Browser Binaries
To switch target browsers, specify the absolute path to the browser executable in executablePath or use short channel names like firefox.
Browser Arguments
Certain argument flags passed to browsers on launch are needed to enable Puppeteer automation. For example in Firefox, we need to explicitly allow remote debugging via:
extraPrefsFirefox: {
‘devtools.chrome.enabled‘: true
}Common Puppeteer Troubleshooting
Most browser launch issues come down to incorrect paths or arguments. If tests hang on browser.wsEndpoint(), check the browser‘s actual DevTools errors for clues. File paths with special characters sometimes need escaping.
Bottom line – test and validate browser configuration locally before moving to the cloud!
Strategies for Writing Resilient Cross Browser Tests
With browsers configured, let‘s discuss patterns for making tests work smoothly across Chrome, Firefox and Edge:
Standard Selectors Over Browser Specifics
Rely more on element IDs, classes, semantics vs browser prefixes or custom attributes when possible:
// Preferred
await page.$(‘.product-tile‘)
// Avoid if possible
await page.$(‘-webkit-product-tile‘) Abstract Browser Differences
Encapsulate browser variances in helper modules instead of littering checks:
// helpers.js
export function getPrice(page) {
if (isFirefox()) {
return page.$eval(‘.fx-price‘, el => el.textContent)
} else {
return page.$eval(‘.price‘, el => el.textContent)
}
}
// test.js
import { getPrice } from ‘./helpers.js‘;
const price = await getPrice(page);Feature Detection Over Browser Checks
Check for specific required features vs detecting browser versions:
if (await page.evaluate(() => ‘IntersectionObserver‘ in window)) {
// Use modern scroll handler
} else {
// Fallback scroll handler
}Plan for Flakiness
Cross browser tests are inherently more flaky – build in flexibility via waits, retries and try/catch blocks.
Per-Browser Conditional Logic
Use browser metadata like page.browser().name or capability checks to include special cases per target browser.
Debug Visually
Leverage headful mode, save screenshots on failures and use browser DevTools to inspect issues visually across browsers.
Unlocking Puppeteer‘s True Cross Browser Superpowers
Executing tests locally across a couple configured browsers provides a solid foundation for compatibility confidence. However, to achieve comprehensive and performant cross browser test coverage, we need to take advantage of specialized cloud testing infrastructure.
Challenges Testing Locally
- Limited Environment Coverage: Only browsers available locally
- Time Consuming: Serial test execution across browsers
- Difficult Debugging: Varies across configurations
- Flaky Failures: Hard to reproduce locally
Powerful Cloud Testing Platforms
Instead of attempting to emulate all required browser, OS and device combinations locally, services like BrowserStack Automate provide instant access to real mobile and desktop environments where we can directly execute tests written in Puppeteer and other frameworks.
Key cloud testing capabilities:
- 2000+ Browsers and Devices: All modern environments
- Parallel Execution: Faster test cycles
- Live Debugging: Visual troubleshooting
- CI Integrations: Pipeline automation
- Test Analytics: Cross browser reports
- Puppeteer Support: Seamless integration
For example, to run my product tests across the latest versions of Edge, Chrome and Firefox on multiple operating systems, I simply modified my Puppeteer scripts with a few lines of BrowserStack configuration:
// Specify BrowserStack credentials
const browserstack = await puppeteer.connect({
browserWSEndpoint: `wss://USERNAME:[email protected]/...`
});
// Queue test on needed browser configurations
const testBrowsers = [
{os: ‘Windows‘, os_version: ‘11‘, browser: ‘Edge‘},
{os: ‘OS X‘, os_version: ‘Monterey‘, browser: ‘Chrome‘},
{os: ‘Windows‘, os_version: ‘10‘, browser: ‘Firefox‘}
];
// Execute tests in parallel
for (testConfig of testBrowsers) {
browserstack.newPage(testConfig);
// Run test logic on page
await page.goto(‘https://mySite.com‘);
// BrowserStack handles session cleanup
}
This executes my test in parallel across real Windows and macOS devices using live interactive browsers, not just mock headless instances.
Now let‘s discuss recommendations for building an effective cross browser testing strategy leveraging cloud services.
Best Practices for Cross Browser Testing Ops
Even with infinite testing infrastructure, we need to align processes for maximizing test efficiency and coverage across browsers:
Structure Test Suites
Group slower browsers like Firefox and Edge separately from fast Chromium test runs. Balance test times across groups.
Retry Flaky Tests
Automatically retry failing Puppeteer tests 1-2 times before declaring actual failure to reduce flakiness.
Configure Timeout Buffers
Provide timeout padding in waiting logic to accommodate varying browser performance. Don‘t overfit values to one browser.
Capture Debug Artifacts
Screenshots, videos and logs during test failures document differences across browsers for debugging.
Track Browser Metrics
Gather test pass %, durations and failures in dashboards to identify browser-specific bottlenecks.
Test Early, Test Often
Include cross browser testing in dev workflows from PR validations through to production monitoring. Fix issues incrementally, not right before launch!
Prioritize User Journeys
Focus compatibility testing on entire real world user flows instead of isolated component behavior. Think end-to-end.
Report Unified Test Results
Output Puppeteer test reports using consolidated formats instead of separate files per browser to enable test analysis across environments. Services like BrowserStack generate these cross browser reports automatically.
Incorporate Real User Monitoring
Complement automation with production monitoring across actual user traffic to surface browser gaps missed in synthetic tests.
Conclusion and Additional Resources
Hopefully this guide has demystified cross browser testing with Puppeteer and provided practical strategies for tackling compatibility confidence at scale. I‘ve personally run thousands of automated browser tests over my career and made all the mistakes along the way so you don‘t have to!
If you found this helpful, I highly recommend checking out these additional resources:
- Advanced Puppeteer Tips and Tricks Guide
- Ebook on CI/CD Best Practices
- Top 50 Web Testing Interview Questions
Feel free to reach out if you have any other questions – I‘m always happy to chat more about browser automation, compatibility challenges and other testing wisdoms!
John Smith
Senior Test Automation Architect
[email protected]
