Testing HTML5 Websites for Cross Browser Compatibility

Have you built a stylish, interactive website leveraging nifty HTML5 features only to be surprised by inconsistent layouts or limited functionality when users access it across different desktop and mobile browsers?

As a web developer with over 10 years of experience testing web apps on thousands of real device and browser combinations, I have learned the hard way how lack of diligent compatibility checks during development can lead to frustrating user experiences post deployment.

This detailed guide aims to help you learn:

• Importance of HTML5 browser compatibility testing
• Top desktop and mobile browsers to test on
• Tools to identify compatibility issues
• Common HTML5 web testing pitfalls
• Fixes and best practices to avoid problems

So let‘s get started on building highly responsive and resilient websites using next generation HTML5 capabilities!

Why Check HTML5 Cross Browser Compatibility

Since its official release in 2014, HTML5 usage has grown tremendously and now accounts for over 90% of all websites as per W3Techs survey trends.

Figure 1 – HTML5 Usage Trend Across Websites

With responsive web design becoming vital for addressing diverse browsing environments, HTML5 introduces several enhancements over its predecessors:

• Multimedia elements like video, audio, graphics
• Form input types – email, phone, date picker
• Connectivity API access – geolocation, web sockets, WebRTC
• Semantic tags for better structure – header, nav, article
• Native device features – camera, microphone, sensors
• Offline storage/caching capabilities

However, delivering consistent user experiences across the mosaic of desktop and mobile browsers poses compatibility challenges for many of these cutting edge features.

Let us take a look at the current market share across top browser platforms to understand testing priority:

Browser	Desktop Share	Mobile Share
Chrome	65.4%	62.99%
Safari	18.7%	25.47%
Edge	4.6%	NA
Firefox	3.59%	0.45%
Internet Explorer	5.62%	NA

Table 1 – Browser Market Share on Desktop and Mobile (Source: StatCounter)

Chrome enjoys majority on both desktop and mobile with Safari and Firefox trailing as nearest competitors. So while testing, ensure HTML5 elements work fine in:

• Desktop: Chrome, Firefox, Safari, Edge, IE11
• Mobile: iOS Safari, Chrome Android, Stock Android browser

Now let us explore common HTML5 web testing compatibility issues and their fixes.

Tools for Checking Browser Compatibility

Specialized browser testing tools help identify levels of HTML5 support across target browsers:

Modernizr – Open source JavaScript library that detects native implementation for next-gen web technologies

CanIUse – Provides up-to-date browser support tables for front-end web technologies

BrowserStack – Cloud testing platform to instantly preview website on 3000+ real desktop and mobile browsers

Figure 2 – Sample HTML5 Compatibility Table on CanIUse

Common HTML5 Compatibility Pitfalls

While HTML5 capabilities usher richer, more dynamic web experiences, the pace of standards adoption causes inconsistent behavior across browser engines.

Let us explore some key HTML5 compatibility trouble areas:

1. Form Elements

HTML5 introduces over a dozen new <input> types like email, date, time, slider to ease form entry on mobile devices.

However, older browsers like IE11 and below do not recognize these new values by default causing uncontrolled fallback to simple text type.

Solution: Use polyfill scripts like webshims to normalize form validation and styling across browsers

2. Media Elements

The HTML5 <audio> and <video> tags allow embedding rich media content without need for external plug-in or player. But support for varied codecs like MP3, AAC, WebM, and Containers across browsers remains fractured requiring format fallbacks.

Table 2 – Audio/Video Format Support Across Browsers (Source: MDN)

Solution: Offer media in multiple formats, containers to maximize playability

3. Semantic Elements

New semantic tags like <article>, <section>, <header> introduced in HTML5 lack inherited styling in IE, appearing as empty containers unless CSS rules applied.

Solution: Explicitly style new elements for consistent appearance by targeting common browsers using prefixes:

header { 
   display: block 
}

.-webkit-header {
  display: block
} 

4. Canvas Element

The <canvas> element facilitates rendering 2D graphics via JavaScript but output quality and fidelity varies based on JS engines of browsers.

Figure 3 – Canvas Demo on Safari, Chrome, Firefox (Source: Stack Overflow)

Solution: Standardize dimensions using width and height attributes for consistency:

<canvas id="canvas" width="500" height="300"> 
  <!-- fallback content -->
</canvas>

Use polyfills like FlashCanvas to support older IE.

Likewise, HTML5 connectivity APIs – geolocation, web storage, WebSockets also demonstrate quirky behavior across browser environments.

Now that we have understood common testing trouble spots, let us explore best practices to avoid HTML5 compatibility issues.

Techniques for Improving Cross Browser Compatibility

Here are some key strategies for delivering resilient HTML5 based websites across diverse browsing environments:

Graceful Degradation – Offer acceptable experience on older browsers lacking full functionality

Progressive Enhancement – Layer newer features over core base functionality for wide reach

Feature Detection – Check for native API support before usage to provide fallbacks

JavaScript Polyfills – Emulate missing capabilities across browsers

Validate Code – Ensure strict validity to web standards for consistency

Accessibility Testing – Support disabled users by meeting standards like WCAG

Real Browser Testing – Preview site on various desktop, mobile platforms to identify layout, navigation, UI issues through services like:

• LambdaTest
• BrowserStack
• Browserling

Automated Testing – Script browser compatibility testing scenarios with Selenium on cloud infrastructure from Sauce Labs, Testingbot etc.

Responsive Web Design – Adapt presentation across varying viewports, devices using fluid grids, flexible images and media queries

Getting in the habit of checking HTML5 compatibility at early stages of development rather than later can significantly improve quality and avoid last minute headaches!

The Road Ahead

The HTML story continues evolving with HTML 6 already in draft state, which adds capabilities like:

• Dialog element for modal dialog boxes
• Encrypted Media Extensions (EME) for DRM protected video
• File API enhancements – slicing blob objects, drag and drop lists
• Better script loading via async/defer attributes

These upcoming features would bring the next wave of browser testing challenges for web developers!

Conclusion

HTML5 provides an arsenal of new elements and attributes to boost website aesthetics, responsiveness and interactivity. However, gaps in standardized feature implementation across Chrome, Firefox, Edge and others can cripple experiences for your users.

Hence conducting structured browser and device testing needs to complement any modern web project undertaking. Luckily advanced cloud testing services provide instant access to thousands of real desktop and mobile browsers.

So take advantage to proactively identify any HTML5 compatibility pitfalls or rendering issues upfront rather than take chances! With a little extra testing diligence, you can ensure stellar, uniform experiences for your audience regardless of the browser environment they access your creations from.

Hope this guide gives you confidence to build and deploy interactive HTML5 websites faster without worrying about cross browser gremlins! Do let me know if you have any other challenges I can help advise on.