As web developers we want to ensure what we build is accessible by as many people as possible, with as many web browsers, operating systems and devices as we can support. It is also hard to know what the future holds, and for that we have put together Writing forward-compatible websites

Topics covered

We see this as a living document, and so far we have information on topics like JavaScript, Feature and User Agent sniffing, Testing, Web browser-specific features and Code hygiene.

Complete contents

The complete content listing is:

• JavaScript
  • Prefix all global variable access in onfoo attributes with “window.”
  • Don’t concatenate scripts you don’t control
  • Ask the authors of any JavaScript libraries you use to also follow these guidelines
• Sniffing
  • Sniff for specific features
  • Don’t UA-sniff
    • If you have to UA-sniff, only sniff for past browser versions
  • Don’t unnecessarily create separate codepaths for different browsers
• Testing
  • Test with all major engines
• Browser-specific features and prefixes
  • Don’t target hacks at current or future versions of browsers
  • Avoid depending on cutting-edge nonstandard features
  • When using cutting-edge features (even standard ones) that are not universally implemented, make sure to test fallback paths
  • Don’t use vendor-prefixed features except to target old buggy versions
  • Don’t use unprefixed versions of CSS properties or APIs until at least one browser supports them
• Code hygiene
  • Avoid missing >
  • Don’t leave experiments that didn’t work in your code

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