HTML and CSS Reference
are no standard fonts, and some mobile browsers offer only one font,
in one size, without bold or italic embellishment. Most devices allow the
user to select different font sizes for the device to accommodate aging
eyes and small displays; these size differences can dramatically affect
the rendering of content on the device's small screen.
Some mobile browsers cannot handle any sort of images in their pages,
although this is becoming less of a problem in more recent mobile
devices. Almost all mobile browsers have a difficult time with large im-
ages and may ignore or alter such images as they see fit. There is no
clear definition of what constitutes a "large" image; it is in the eye of the
browser and may be determined by both image dimensions and over-
all size. Formatting and wrapping of text with images is inconsistent,
and mobile browsers often ignore image alignment attributes altogeth-
er. Needless to say, the current generation of devices cannot handle any
sort of embedded video, flash, or animated content in any form.
14.2.2. Input Constraints
Cellular phones lack the single most convenient input device that makes
the desktop browser successful: a mouse. PDAs and convergence
devices do not suffer this limitation, typically allowing the user to tap
on the screen with a stylus, but the majority of your target audience
for mobile content is using a cellular phone. Consequently, general page
navigation is a chore on mobile devices. Moving the focus within a page
to select a link can be tedious at best, especially when there are several
links to navigate among.
Entering text on a cellular phone is tiresome, too. Most phones offer two
text entry modes: a multitap mode where pressing a key cycles through
the letters on that key, and a predictive mode where the user adds let-
ters until the phone finds the desired word based on the letter pattern.
The former is tedious but ultimately more accurate; the latter may be
quicker, but usually fails because typing URLs is the most common mo-
bile web activity and does not follow typical spelling patterns.