Don't touch the mobile partsFrancesco Fullone <ff@ideato.it> Twitter @fullo

Who am I

Francesco Fullone aka Fullo

- PHP developer since 1999

- President

- and Open Source Evangelist

- CEO @

- founder @

- Nerd and geek

In the previous* WPO episodes

* “don't touch the slow parts ” [ http://ow.ly/5ihyb ] and “extended slow parts” [ http://ow.ly/5ihLT ]

Kate and Jack discovered that the 80% of loading time

is on the browser

In the same time Lockeunderstood that

resource loading order matters

Sayid tried to cut the bandwidth usage

decreasing files number and size...

… helped by Hurley whomreduces downloads forcing

headers to enable browser cache

at the same time, the “Others” studied the new possibilities offered by the

HTML5

They never believe thatmobile WPO is an even more

mysterious and frightening journey...

...and that 97% of performance issues happen at frontend*

* from webperformancetoday.com [ http://ow.ly/5hd35 ]

The Browser Chapter

On a smartphone a web pageis rendered from 40% to 80% slower

than on a desktop.

A lot of different browsers

Pre-installed webkit(iOS, Android, Blackberry, webOS, Symbian …)

Pre-installed non-webkit(Bada, old Blackberry, Internet Explorer, DoCoMo …)

User installable(Opera Mobile/Mini, Firefox, Skyfire ...)

Same engine doesn't meansame behaviours

We have to talk about mobile browser families:

SmartphoneMid-EndLow-End

Mid-End to Low-End browsers families lost (randomly):

HTML5 supportCSS3 support

Caching quotaAjax

Still...

Symbian's Anna WebKit browser* has

No Application CacheNo Geolocalization APINo HTML5 Audio/Video tagsVery limited CSS3 support

* Released on April 2011 for X7 and E6 Nokia Smartphones

CSS Expressions and iFrames don't work on most mobile browsers

Different country* means different browser

* From icrossing.co.uk [ http://ow.ly/5hanY ]

Caching, now, is not a difficult task

* browserscope.org helps us [ http://ow.ly/5h8Db ]

New iOS* and Android browsers have

4Mb file cache (uncompressed)4Mb total cache (uncompressed)1Mb limit for file execution (js/css)

* but cache is invalidated at the reboot [ http://ow.ly/5h8G4 ]

But...

Old iOS 3.x browser* had

25.6Kb file cache1Mb total cache (uncompressed)

* and a lot of other low-end browsers

The Network Chapter

3G Networks are slow, with higher latency and limited*

* comet doesn't works and 3G operator applies some limits.

HTTP Headers are different*[...]

user-agent: LG-CU920/V1.0p Obigo/Q05A Profile/MIDP-2.0 Configuration/CLDC-1.1via: 1.1 alpmagr1fe02WAP2-mbl

x-up-devcap-accept-language: en,fr,esx-up-devcap-charset: US-ASCII,ISO-8859-1,UTF-8,UTF-16,ISO-8859-15,ISO-10646-UCS-2

x-up-devcap-iscolor: 1x-up-devcap-numsoftkeys: 3x-up-devcap-screendepth: 16

x-up-devcap-screenpixels: 240,400x-up-devcap-smartdialing: 1

x-up-subno: ppu_1077a8d8fc1_vmag.mycingular.netx-wap-profile: http://gsm.lge.com/html/gsm/LG-CU920.xml

[...]

* 30% more than desktop, ETag doesn't works

Beware of the content proxies*!

* used by some browsers like Opera mini. Ajax doesn't work properly

The Mobile WPO Chapter

As for desktop browsers a reduction of the requests is necessary,

but mobile strategies are somewhat differents

When possible embed resources in the page: CSS, JavaScript* and images

with data URI

* then save them after document.onload in local cache

Use Application Storage to statically save most used resources and user

infos* in localStorage

* as the geolocation infos and prefs

Save JavaScript function with Application Storage*, then fire them

to a tag and eval when needed

* as Google and Bing do [ http://ow.ly/5h8Ab ]

Load resources as late as possible* and store them to be never loaded

again

* use ajax and infinite scrolling pattern [ http://ow.ly/5h9A6 ] to load only visible data, but remember to free memory

Use CSS to draw interface object*-webkit-border-image, CSS sprites, -webkit-border-

radius, -webkit-gradient, ...

* but remember that the browsers compatibility changes

Optimize images* and defer them when possible. Use SVG for charts.

* animated GIF doesn't work on Android and WebOS, SVG is not enabled on Android. When possible strip EXIF tags.

GZip, Minify and Merge CSS and JavaScript*

* as usual ;)

When possible avoid JavaScript frameworks*

and use specific ones (ie. zepto.js)

* some mobile browser can take up to 8s to parse jQuery

Detect device, reduce image details as needed

* use window.devicePixelRatio on WebKit

HTML coding still matter

Use different (KiSS*) html than in the desktop browser

* reduce elements. You are still on a 3/4'' device, isn't it?

Reduce DOM elements, CSS classes and apply good programming

patterns

Add specificic html meta tags* for mobile browsers

* viewport, media=handheld, MobileOptimized, HandheldFriendly

* add the right MIME for each device and use viewport meta tag

Test your code

http://mobile.httparchive.org

http://blaze.io/mobile

http://jdrop.org

http://www.mobilexweb.com

Your new best friend*

* buy it on Amazon http://ow.ly/5sm6C

via Quinto Bucci 20547023 Cesena (FC)

info AT makemeapp.itwww.makemeapp.it

Francesco Fulloneff@ideato.it

@fullo