HTML and CSS Reference
In-Depth Information
• Modular,
• E
!
cient,
• Typographically rich.
Progressive Enhancement
Progressive enhancement means creating a solid page with appropriate
markup for content and adding advanced styling (and perhaps scripting) to
the page for browsers that can handle it. It results in web pages that are
usable by all browsers but that do not look identical in all browsers. Users of
newer, more advanced browsers get to see more cool visual e
"
ects and
nice usability enhancements.
The idea of allowing a design to look di
"
erent in di
"
erent browsers is not
new. CSS gurus have been preaching this for years because font availability
and rendering, color tone, pixel calculations and other technical factors have
always varied between browsers and platforms. Most Web designers avoid
“pixel perfection” and have accepted the idea of their designs looking
slightly di
"
erent in di
"
erent browsers. But progressive enhancement, which
has grown in popularity over the past few years, takes it a step further.
Designs that are progressively enhanced may look more than slightly
di
"
erent in di
"
erent browsers; they might look
very
di
"
erent.
For example, the tweetCC website has a number of CSS 3 properties that
add attractive visual touches, like drop-shadows behind text, multiple
columns of text and di
"
erent-colored background “images” (without there
having to be actually di
"
erent images). These e
"
ects are seen to various
extents in di
"
erent browsers, with old browsers like IE 6 looking the
“plainest.” However, even in IE 6, the text is perfectly readable, and the
design is perfectly usable.
