If you're perusing one of my articles on blog coding, for instance Centering Complex and Multiple Objects , and you follow my advice to read the W3 Schools tutorials for further advice, you'll find a lot to read. They give you good canonical definitions of each HTML tag, and interactive exercises so you can see what each one actually does. If you're reading about the <center> tag , you'll note the advice The center element was deprecated in HTML 4.01. The center element is not supported in XHTML 1.0 Strict DTD. If you're not blocking popups from http://www.w3schools.com , you'll note a popup window advising you that A deprecated element or attribute is one that has been outdated. Deprecated elements may become obsolete in the future, but browsers should continue to support deprecated elements for backward compatibility. In other words, you can keep using <center> ... </center> right now, but one day in the future, it may stop working. No gua...
What Blogger won't tell you