HTML5

on Mobile


 

Gonthier Olivier (@rolios)

Reminder


1989: HTML is created
1994: W3C, HTML 2.0
1996: Apparition of CSS, JavaScript
1997-98: HTML 3.2,  4.0, CSS2
2000-2006: HTML left, XHTML born
2004: WhatWG, HTML is back
2007: W3C + WhatWG on HTML
2008: Apparition of HTML5
...
2014: Final Release?

Reminder



HTML5 = HTML + JS + CSS

Specification (RC): w3.org/TR/html5

Common base of all mobile systems

Resources






What can we use on Mobile?



Media-Queries (css3)





Responsive design

Media-Queries


<link type="text/css" href="smallscreen.css" rel="stylesheet"
   media="screen and (max-width:480px)" />
header {
   width: 80%;
}

@media screen and (max-width:480px) {
   header {
      width: 100%;
   }
}

Geolocation


Get position of the user, or track movements


var geolocAPI = navigator.geolocation;
var opts = { timeout: 10000 };

geolocAPI.getCurrentLocation(successCallback, errorCallback, opts);
geolocAPI.watchPosition(successCallback, errorCallback, opts);

function successCallback(e){
   console.log(e.coords.latitude + ", " + e.coords.longitude);
}

Websocket


Bi-directional communication server/client

var ws = new WebSocket("ws://mycoolserver.com");

ws.onopen = function(e){ // communication ready }
ws.onerror = function(e){ // something wrong happened }
ws.onclose = function(e){ // communication stopped }

ws.onmessage = function(e){
   // Server sent us a message!
   console.log(e.data);
}

//Let's reply
ws.send("Thanks man!");

XmlHttpRequest-v2

Async queries, new version (AJAX)


New version give us: 

  • CORS
  • New data types (Files, formdata, arraybuffer)
  • precise progression
var data = new FormData();
data.append('name', 'john');

var xhr = new XMLHttpRequest();
xhr.open('POST','http://mycoolserver.com/survey/42');

xhr.send();

xhr.onload = function(e){ // result }

Storage


  • LocalStorage / SessionStorage
    - Simple key/value storage

  • WebSQL
    - Relational db, deprecated

  • IndexedDB
    - Document storage

Storage

// LocalStorage
localStorage[name] = "John";
alert("hello, "+ localStorage.name);
// WebSQL
var db = openDatabase("myAppDB", "1.0", "books", 1024*1024);
db.transaction(function (t){
   t.execuleSql("SELECT * FROM books", _, onSuccesCallback);
}
// IndexedDB
var openRequest = indexedDB.open("myAppDB", 1);
openRequest.onsuccess = function(e){
   var db = e.result;
   var tx = db.transaction(["books","readwrite"]);
   var store = tx.objectStore('books');
   //Add data
   store.add({title: "html5 on mobile", author: "me"});
   //Get Data
   store.get(1)}

Webworkers

A solution to run long scripts
var worker = new Worker("myScript.js");

//myScript is launched, you can communicate by event messages

worker.postMessage("hello script");

worker.onMessage = function(e) {
   console.log(e.data);  
}
No more:

Application Cache

Cache some static resources,
Offline is Important!

 <html manifest="cache.manifest">
CACHE MANIFEST
# version 2.51

img/logo.png
styles/design.css

FALLBACK:
/img/online.png /img/offline.png

NETWORK:
script/websocket.js

An example: stackedit.io continue to works offline

WebRTC

Peer-to-Peer Real Time Communication

  • Ideal for voice communication

  • Experimental for now 

  • Not enough support on mobile


(Complex process to make it works)

Bistri is an example of service using it.

Touch events

(Spec not part of html5)


DOM events for touch action

 <div id="touchzone">This is touchable</div>

<script>

var zone = document.getElementById("touchzone");
zone.addEventListener('touchstart', function(e){});

zone.addEventListener('touchmove', function(e){
   console.log(e.screenX, e.screenY);
});

</script>

Difficulties


Because mobile dev is sometimes hard...

  • Specific UI (Small touch screen)
  • Fragmentation, cross-os support
  • Battery consumption
  • Client-side app
  • Unstable connectivity

Difficulties

Some advices

  • Think Offline before, then "connect" your app
  • Do not make too much http request
    • Do not use SSE (=polling!)
  • Try to send error logs to server when possible
  • Give voice to your users
  • UI must be minimalistic 
    (Only display what the users want to see)
  • Test on real devices

Useful tools

debug, management, ...



Debug tools




NPM

(Node) Package Manager
-
Manage your dependencies
npm search jquery

# Get depency in current project repository
npm install jquery

# Or, install on global system
(sudo) npm install -g jquery

Grunt

Manage the lifecycle of your project

npm install -g grunt
grunt clean
grunt build
grunt serve
grunt test
...
Projects can define specific behavior in a gruntfile.js

Yeoman



Yeoman = Yo + Bower + Grunt

Yo generates projects so that you can start quickly
Bower take care of your depencies

And others...


Very (very) active community!

Webjars, Gulp, Brocoli, and so on.



Questions



HTML5 on mobile

By Gonthier Olivier

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