The Device Matrix

TABLE 11-1 provides a listing of popular browsers and their assigned classes, starting with A, the highest grade, to be considered on par with desktop browsers, and ending with F, the lowest possible grade.

TABLE 11-1: The device matrix

Class	Markup	CSS	JavaScript
Class A	XHTML, XHTML-MP, HTML5	CSS2, CSS3	Great, includes DHTML, Ajax
Class B	XHTML, XHTML-MP	CSS2 (Decent)	Limited, some DHTML
Class C	XHTML, XHTML-MP	CSS2 (Limited)	Limited
Class D	XHTML-MP	CSS2 (Basic)	None
Class F	XHTML-MP, WML	None	None

Class A mobile browsers

Some of the characteristics of a Class A mobile browser are:

Excellent XHTML 1.0 support
Good HTML5 support; specifically, the `canvas` element and offline storage
Excellent CSS support, including most of CSS Level 2.1 (scores 90 percent or higher on the ACID2 test) and the majority of CSS Level 3 (scores 75 percent or higher on the ACID3 test)
Support for web standards layouts, including absolute positioning, floats, and complex CSS-based layouts
Support for image replacement techniques
Excellent JavaScript support
Ability to toggle the display property
Support for DOM events, including Ajax
Considered comparable to a “desktop-grade” browser

Class B mobile browsers

Some of the characteristics of a Class B mobile browser are:

Excellent XHTML 1.0 support
Good CSS Level 2.1 support (scores 75 percent or higher on the ACID2 test)
Padding, border, and margin properties are correctly applied
Can reliably apply colors to links, text, and background
Supports image replacement techniques
Minimum screen width: 164 pixels
Can support complex tables—not necessarily nested tables—up to four cells in a row
Setting a font size of 10 pixels or more produces readable text
Has limited JavaScript support, being at least able to toggle the display property

Class C mobile browsers

Some of the characteristics of a Class C mobile browser are:

Good XHTML 1.0 support
Limited CSS Level 2.1 support (scores 50 percent or higher on the ACID2 test)
Limited or no JavaScript support

Class D mobile browsers

Some of the characteristics of a Class D mobile browser are:

Basic XHTML
Limited CSS support (CSS Level 1, or does not recognize cascading)
Minimum screen width: 120 pixels
Hyperlinks may not be colorable by CSS
Basic table support: 2×2 or more
`colspan` and `rowspan` may not be supported
“Width” expressed as a percentage may be unreliable
No JavaScript support

Class F mobile browsers

Some of the characteristics of a Class F mobile browser are:

No (or very unreliable) CSS support
Poor table support or none at all
Basic forms: text field, select option, submit button
May not be able to support input mask on fields
No JavaScript support