Frequently people ask me why is it so important to use "standard", validated HTML code, even when they correctly see the page in their preferred browser.

"All browsers know how to deal with correct HTML.

However, if it is incorrect, the browser has to repair the document, and since not all browsers repair documents in the same way, this introduces differences, so that your document may look and work differently on different browsers."

While for a long time webmasters have opted to code for Internet Explorer forgetting altogether compatibility issues and respect for open standards, now that IE is going not to be anymore our browser of choice, we are seeing many sites that while work fine in IE, do not look so good when viewed in Mozilla, Opera or Safari.

Since there are hundreds of different browsers, (and browser like engines - see for example Google, the Google Deskbar, etc.) and more coming all the time (not only on PCs, but also on PDAs, mobile phones, televisions, printers, even refrigerators), it is impossible to test your document on every browser. So you can take the following reference rule with you:

If you use non-standard (non-validated) XHTML (or HTML) and your document doesn't work on a particular browser, it is your fault; if you use standard, validated (X)HTML and it doesn't work, it is a bug in the browser. This is the only way we are going to come out of this mess.

Where can you go to verify if your Web pages utilize correct XHTML markup? W3C offers an official public validator service. How can you test your web page on as many different Web browsers and operating systems as possible? Browsercam remains the only answer. Go check out their great service.

Which tool can convert your HTML into XHTML? HTML Tidy is the answer. Go download this free great support utility now.