Center is an element that centers the text it contains in the browser
window. The element was created to fill the need for authors to have some text
alignment controls, but most of the effects this element produces have been
absorbed by other block formatting elements as the ALIGN attribute (which
extends control to right alignment and justification as well.)
The interaction rules for this element are somewhat unusual since it
was created by Netscape and implemented by many other browsers before it was
officially integrated in to HTML 3.2. CENTER behaves most closely like other block
formatting elements (in that a block is defined by having a linebreak before and
after the contained content.)
The CENTER element has a parent/content model that is much
less strict in practice than other block formatting elements do.
It is often used to encompass other block formatting elements.
Until HTML 3.2 it was considered better HTML authoring to
use the P ALIGN or DIV ALIGN elements, but now that argument holds less
weight than it once did.
Use of P ALIGN and DIV ALIGN DO allow a greater range of
alignment options for the author.
CAVEAT: Use of any of the currently valid alignment properties to
center tables structures (CENTER, P ALIGN & DIV ALIGN) will have
an unfortunate effect on browsers that understand alignment properties
but do not understand tables: It will center all the table contents.
This can render useless most attempts to degrade tables gracefully and
can create very odd looking results. Remember to try viewing your pages
on browsers with different capabilities!
DTD NOTE: Alignment tags/attributes do not
react very well with Netscape's MULTICOL element.
Browser Peculiarities
Tables capable browsers need either a CENTER element or a DIV
ALIGN=CENTER element to center an entire table.