making your site mobile-friendly - devcsi reading 21.07.2010
DESCRIPTION
Extended version of my "Making your site mobile-friendly" talk, including a short look at native applications vs web apps, for the UKOLN DevCSI event "Developing for Mobile Applications in Education" in Reading http://www.ukoln.ac.uk/events/devcsi/mobile_applications/TRANSCRIPT
Making your site mobile-friendly TIPS AND TECHNIQUES FOR A BETTER MOBILE PRESENCE
Patrick H. Lauke / Developing for Mobile Applications in Education / DevCSI / Reading / 21 July 2010
mobile web is increasingly important
we need a site that works on iPhone
...works on iPhone...oh, and iPad
“remove iPhone from ass”Peter-Paul Koch, The iPhone obsession
www.quirksmode.org/blog/archives/2010/02/the_iphone_obse.html
make your site work on all (most) mobile devices
1. do nothing
not WAP or text anymore...
mobile browserswill work ok-ish
“But the mobile context...”
2. separate mobile site(m.flickr.com, mobile.mysite.com, ...)
beware browser sniffingphoto: http://www.flickr.com/photos/timdorr/2096272747/
offer users choice:desktop or mobile?
refactored for small screen,not dumbed down for mobile
3. single adaptive site
nothing new...fluid layout, progressive enhancement, graceful degradation
CSS 2 Media Types(screen, print, handheld)
CSS 2.1 Media Types
<link rel="stylesheet" ... media="print" href="...">@import url("...") print;@media print { // insert CSS rules here}
CSS 3 Media Queries“...the new hotness” Jeffrey Zeldman
http://www.zeldman.com/2010/04/08/best-aea-yet/
CSS 3 Media Queries
● build and extend CSS 2.1 Media Types● more granular control of capabilities● width, height, orientation, color, resolution, …
http://www.w3.org/TR/css3-mediaqueries/
CSS 3 Media Queries
<link rel="stylesheet" ... media="screen and (max-width:480px)" href="...">@import url("...") screen and (max-width:480px);@media screen and (max-width:480px) { // insert CSS rules here}
viewport meta
viewport meta
● desktop: viewport = visible area of browser● mobile: “virtual viewport”, physical pixels, zoom● viewport meta gives hints
viewport meta
<meta name="viewport" content="width=device-width"><meta name="viewport" content="width=320, initial-scale=2.3,user-scalable=no">http://developer.apple.com/safari/library/documentation/AppleApplications/Reference/SafariWebContent/UsingtheViewport/UsingtheViewport.html
minimise dataand server requests
(minify JavaScript, combine CSS, …)
minimise data
● data transfer over network can be slow● compress images (PNGCrush)● optimise your HTML (death to div-itis)● minify JavaScript● combine CSS
minimise server requests
● each request has overhead● limit to concurrent requests● caching not reliable (e.g. iPhone > 25Kb)
CSS spritesDave Shea, A List Apartwww.alistapart.com/articles/sprites
width: 50px; height: 50px;background: url(icons.gif) no-repeat -51px 0;
data URLshttp://software.hixie.ch/utilities/cgi/data/data
data URLs
<img width="48" height="48" alt="Redux gravatar" src="data:image/jpeg,%FF%D8%FF%E0%00%10JFIF%00%01%01%01%00H%00H%00%00%FF% … ">h1 {
background: url("data:image/jpeg,%FF%D8%FF%E0%00%10JFIF%00%01 … ") no-repeat left top;}
native app vs web app
HTML5<!DOCTYPE html>
video, audio and canvas on any devicewithout plugins
(Java / Flash / Silverlight not ubiquitous)
HTML5 (and friends) haslots more APIs for developers
(for powerful client-side apps)
geolocationnavigator.geolocation.getCurrentPosition(success, error);navigator.geolocation.watchCurrentPosition(success, error);function success(position) {
/* where's Wally? */var lat = position.coords.latitude;var long = position.coords.longitude;...
}
offline detection...
window.addEventListener('online', function(){ … }, true);window.addEventListener('offline', function(){ … }, true);
application cache<html manifest=”blah.manifest”>CACHE MANIFESTimages/sprites.pngscripts/common.jsscripts/jquery.jsstyles/global.cssdata.xmlNETWORK:resources/news.xmlFALLBACK:images/ offline/not-available.png
…and more (coming)WebGL, <device>, Contacts API …
1. do nothing2. separate mobile site3. single adaptive site
www.opera.com/[email protected]
people.opera.com/patrickl/presentations/devcsi-mobile_21.07.2010/devcsi-mobile_21.07.2010.pdf