Center

Center Support Key: [2\|3\|*3.2\|4] [X1\|X1.1] [IE1\|M2FB\|N1\|O2.1*]	What is it? Attributes Tag Example	Parent/Content Model Tips & Tricks Browser Peculiarities
= Index DOT Html by Brian Wilson =

Quick Statistics
End Tag:		Required
Standards Details:		HTML: 4.x: Transitional and Frameset DTDs only XHTML: 1.0: Transitional and Frameset DTDs only
XHTML Modules:		Legacy
CSS 'display' Type:		"block"
CSS Mapping:		text-align: center
Default Rendering:		Centered content block
Official Docs:		HTML 4.x, XHTML 1.0

What is it?: Center is an element that centers the content it contains within its parent block element. The element was created to fill the need for authors to have some extra text alignment controls, but the effects this element produces have been absorbed by other block formatting elements as the ALIGN attribute and in CSS as the 'text-align' property (extending alignment control to right alignment and justification as well.)

The interaction rules for this element are somewhat relaxed since it was created by Netscape and implemented by many other browsers before it was officially integrated into 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.)

Common Attributes
%Core%: [2|3|3.2|4] [X1|X1.1] [IE3|M|N4B2|O3.5]
%Accessibility%: [2|3|3.2|4] [X1|X1.1] [IE4B1|M|N6|O5]
%Events%: [2|3|3.2|4] [X1|X1.1] [IE4B1|M|N6B1|O4]
%Language%: [2|3|3.2|4] [X1|X1.1] [IE4|M|N6B1|O]
%Editing%: [2|3|3.2|4] [X1|X1.1] [IE5.5|M|N|O]
Specific Attributes
Align
[2|3|3.2|4] [X1|X1.1] [IE|M|N|O4]: Standards Details: NA; Required? No; Description:
This indicates the horizontal alignment of the content in this block element relative to the browser window.; Values: Left [DEFAULT] | Center | Right
Height
[2|3|3.2|4] [X1|X1.1] [IE|M|N|O4-6.x]: Standards Details: NA; Required? No; Description:
This attribute explicitly specifies the height of this block element in pixels.; Values: Positive integers.
Width
[2|3|3.2|4] [X1|X1.1] [IE|M|N|O4-6.x]: Standards Details: NA; Required? No; Description:
This attribute explicitly specifies the width of this block element in pixels.; Values: Positive integers.

Markup example and Tests

<center>Centered text</center>

Tips & Tricks

The CENTER element has a parent/content model that is much less strict in practice than other block formatting elements are. 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 to center content, but HTML 3.2 gave CENTER its official "blessing" by including it in the standard. The newest versions of HTML/XHTML are phasing out many of HTML's presentation attributes in favor of CSS, and CSS DOES allow greater presentation control than CENTER.
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 of 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

[Test] Tables capable browsers will need either a CENTER element or a DIV ALIGN=CENTER element to center an entire table. TABLE ALIGN=CENTER may also work for this purpose.
[Test] Opera 4.0: This is one of those occasions where you just have to scratch your head - an element whose explicit purpose is to center content can be used to left and right align content as well with the ALIGN attribute.