Cross-Browser Testing Checklist

Your app may work perfectly in Chrome but break in Safari. AI-generated code frequently uses CSS features, JavaScript APIs, and HTML patterns that behave differently across browsers. This checklist ensures your app works consistently for all users, regardless of their browser choice.

Last updated: 2026-03-14

Visual Consistency

Layout renders correctly in all major browsers

Compare the layout in Chrome, Firefox, Safari, and Edge to verify consistent rendering of all structural elements.

Fonts render consistently

Check that custom fonts load and render correctly in all browsers, with acceptable fallback fonts when loading fails.

Colors and gradients display correctly

Verify that CSS colors, gradients, and opacity values produce the same visual result across browsers.

Flexbox and Grid layouts work everywhere

Check that CSS Flexbox and Grid layouts render correctly, especially in Safari which has known differences.

Functional Consistency

Form inputs behave consistently

Test date pickers, number inputs, and file inputs which have different native implementations across browsers.

JavaScript features work in all targets

Verify that modern JavaScript features used in the app are supported or polyfilled for all target browsers.

CSS animations and transitions work

Check that all animations play smoothly and transitions complete correctly in every browser.

File downloads work in all browsers

Test any file download functionality and verify files download correctly with the right name and format everywhere.

Clipboard operations work

Test copy and paste functionality across browsers, as clipboard API support varies significantly.

Safari-Specific Issues

100vh does not overflow on iOS Safari

Verify that elements using 100vh do not extend behind the address bar on iOS Safari, which has a dynamic viewport.

Date input fallbacks work

Check that date inputs display correctly in Safari which renders the native date picker differently than Chrome.

CSS backdrop-filter works or has fallback

Verify that backdrop-filter effects either work in Safari or have an acceptable visual fallback.

Smooth scrolling works

Test scroll behavior smooth in Safari which historically has had inconsistent support for CSS smooth scrolling.

Edge Cases

App works with browser extensions installed

Test with common extensions like ad blockers to verify they do not break your app functionality or layout.

Printing produces acceptable output

If users might print pages, verify the print stylesheet produces readable output across browsers.

Browser zoom levels do not break layout

Zoom in and out in each browser and verify the layout remains functional at 75%, 100%, 125%, and 150%.

Right-to-left text displays correctly if supported

If your app supports RTL languages, verify that the layout mirrors correctly in all browsers.

Frequently Asked Questions

Which browsers should I prioritize for testing?

Chrome and Safari cover roughly 85% of web users globally. Add Firefox for standards compliance and Edge for corporate users. Check your analytics to see which browsers your specific audience uses.

Do I need to test in Internet Explorer?

No. Internet Explorer was officially retired by Microsoft. If you have specific enterprise requirements for IE, use a compatibility mode rather than developing for IE directly.

Let human testers run through this checklist for you

Submit your app and our testers will find the bugs you missed. Starting at €15 per test.

Related checklists

Mobile Responsive Testing Checklist

Mobile responsive testing checklist for AI-generated web apps. Verify layouts, touch interactions, and performance across devices and screen sizes.

Accessibility Audit Checklist

Accessibility testing checklist for AI-generated apps. Cover WCAG compliance, keyboard navigation, screen readers, and color contrast requirements.

Pre-Launch Testing Checklist

Complete pre-launch testing checklist for AI-generated apps. Cover functionality, performance, security, and UX before going live with real users.

← Back to Checklists