Valid Code

Why write valid code?

• Using valid code is best way to ensure that pages display and perform as intended. Invalid code often works on some browsers, but not others, so we might not spot problems.
• Make sure pages validate can lessen troubleshooting time in the future. Even when code displays and performs properly everywhere, it might not be written properly and can cause problems or conflicts when future (valid) elements are added.
• Valid code is not only most usable in terms of browsers, it's also more usable to those who are visually or phyisically handicapped. Images with missing alt tags, for instance, are very common and also very easy to fix.
• Valid code will be supported by future browsers, whereas invalid code might not. Owen Briggs wrote about this in an explanation for a workaround, titled Does it matter?

All of our code doesn't validate. There is some code we've decided to use even though it doesn't validate because it does the most good for the majority of users (you can't please everyone all the time). And there is some code beyond our control, such as in OAS scripts, pages on external (vendor) servers, third-party ads, etc.

But we get as close as reasonably possible.

The World Wide Web Consortium (W3C) provides both a HTML Markup Validation Service and a CSS Valiation Service.

The HiSoftware CynthiaSays portal is a joint Education and Outreach project of HiSoftware, ICDRI, and the Internet Society Disability and Special Needs Chapter. It checks for Section 508 compliance.