Top 10 HTML5 features

Top 10 HTML5 featuresevery developer should

knowGill Cleeren@gillcleeren

Hi, I’m Gill!Gill CleerenMVP and Regional Director.NET Architect @ OrdinaTrainer & speaker

@gillcleeren

[email protected]

Agenda

New elements

Data input &

validationSVGCanvas

Audio &

video

Feature detection Geolocation Local storage

Drag And

Drop File API

New elements 1

There are a lot of new elements in HTML5• <canvas>• <audio>• <video>• <source>• <track>• <embed>• <datalist>• <keygen>• <output>• <bdi>• <wbr>

• <article>• <aside>• <footer>• <details>• <summary>• <figure>• <figcaption>• <mark>• <time>• <meter>• <dialog>

• <command>• <progress>• <ruby>• <rt>• <rp>• <header>• <hgroup>• <nav>• <section>• <main>

Why…?

Let’s take a look at some of them.

<article>

<article></article>

article

Blablabla…

<aside>

<aside></aside>

aside

<audio> & <video>

<video><source src="sample.mp4"><source src="sample.ogv"><source src="sample.webm">Sorry, your browser is too old for this…

</video>

audio

video

<canvas>

<canvas></canvas>canvas

<details> & <summary>

<details> <summary> Sessions </summary> <p>HTML5 what’s new</p></details>

summary details

<figure> & <figcaption>

<figure> <img src="mountain.png"></figure><figcaption> Screenshot of mountain</figcaption>

figure figcaption

<header> & <footer

<header></header><footer></footer>

header

footer

<main>

<main></main>

main

Blablabla…

<section>

<section></section> section

<mark>

<mark></mark>

mark

<meter>

<meter min="0" max="100" value="30"> 30 percent </meter>

meter

<progress>

<progress value="30"></progress>

progress

<nav>

<nav></nav>

nav

<time>

<timedatetime="2014-04-17T22:23:24-8:00">April 17th, 2014</time>

time

New elements

DEMO

Data input and validation2

New ways of input

• HTML5 adds support for common scenarios• Previously done often using JavaScript

• Added: • Date pickers

• Rendered by the browser• Sliders• Email• URL• …

Date and time pickers

• New input type

• Supports date, month, week, time, datetime…• Support in most browsers isn’t optimal though

<input type="date" name="birthDateTextBox" value="2014-1-16" />

This is what IE11 is doing…

Other new input types

• Type • Email

• Error balloon will be shown when not valid• url• tel (adds no extra behaviour)• search (adds no extra behaviour)

<input type="email" name="txtEmail" value="[email protected]" /></br><input type="url" name="txtUrl" value="http://www.techorama.be" /></br><input type="tel" name="txtPhoneNumber" /></br><input type="search" name="txtSearch" /></br>

More new input types

• Type• number• range• color

<input type="number" name="ageTextBox" /><input type="range" name="ageTextBox" min="0" max="100" /><input type="color" name="carColorTextBox" />

New behaviors

• Text fields now support placeholder attribute• autofocus sets the focus on a particular input• Using autocomplete, we set the browser to remembering previous

values• And form can be used to separate an input type from the form

Data validation

• novalidate can be used to specify that validation shouldn’t trigger on the form

• Type range can be used to specify boundaries for the values

<form id="myLoginForm" novalidate="novalidate"> <input type="text" name="usernameTextBox" required="required" /> <input type="password" name="passwordTextBox" required="required" /> <input type="submit" value="Sign In" /></form>

<input type="range" min="0" max="100" step="5" />

Data validation

• New attributes• required• pattern• maxlength

<input type="text" name="usernameTextBox" required="required" /><input type="text" pattern="\d{5}" name="zipCodeTextBox" /><input type="text" name="firstNameTextBox" maxlength="10" />

Data input and validation

DEMO

Canvas 3

What is a canvas?

• Drawing surface• Inline element, flows with content

• No visual by default• JavaScript API only• Content can be set to fallback content

• Supports 2D drawings• Performance may not be consistent across

browsers• Can use GPU

• Supports CSS

When should I use a canvas?

• Games• Multimedia apps• Charts

• Supported in most modern browsers!

Working with the canvas

• Create a <canvas>• Use document.getElementById() to find the canvas by id from

JavaScript• Get hold of the 2d context• Create your drawings from JavaScript code

<canvas id="myCanvas" width="300" height="150"></canvas>

var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");

Drawing, drawing and … more drawing!• Shapes

• Rectangles

• Paths• Lines• Arcs• Beziers• Rectangles• Clipping

• All done a pixel-basis, not vector-based!• Support for transformations• Animations are not supported

• Work using JavaScript though

context.fillRect(x, y, width, height);context.strokeRect(x, y, width, height);context.clearRect(x, y, width, height);

Creating a path

context.beginPath();context.moveTo(100, 75);context.lineTo(75, 100);context.lineTo(25, 100);context.fill();

Drawing text

• Adding text is similar to adding shapes• font can be used using CSS• In general, drawing text can fall back on CSS

• Supports alignment • Horizontal and vertical

• No multiline supportcontext.fillText(text, x, y);context.strokeText(text, x, y);

Drawing images

• Image can be added onto the canvas• Can come from img, video or other canvas

• Use the drawImage method

var image = document.createElement("image");image.onload = function () { context.drawImage(image, 10, 10);;{image.src = "logo.png";

Canvas

DEMO

What is SVG?

• SVG == Scalable Vector Graphics• XML model embedded in HTML• <svg> tag• Part of the regular DOM

• Pretty old (2001), revisited in 2011• Allows for vector-based, scalable graphics• Can sometimes replace the use of images and thus load faster

<svg version="1.1" xmlns="http://www.w3.org/2000/svg"></svg>

Drawing in svg

• We can add shapes within the <svg>• Rectangles• Circles• Ellipse• Lines• Polylines• Polygons• Text

<svg width="100" height="100"> <circle cx="50" cy="50" r="40" stroke="green" stroke-width="4" fill="blue" /></svg>

Drawing in svg

<rect x="30" y="30" width="100" height="60" />

<circle cx="50" cy="30" r="20"/>

<ellipse cx="400" cy="200" rx="350" ry="150" />

<polygon points="15 5, 100 8,6 150" />

Drawing in svg

<line x1="100" y1="300" x2="300" y2="100" stroke="b" />

<polyline points="50,375 150,375 150,325 250,325 250,375 350” />

<path class="SamplePath" d="M100,200 C100, 100 250, 100 250, 200 S400, 300 400, 200" />

Basic styling in svg

• Using Filters, we can apply better graphical effects• Creating blurs and shadows• Less resources to download

• Filter is a series of operations applied on an element• Uses defs element: contains definitions of elements such as filters• Defines a x, y, width and height where the filter is applied

<svg version="1.1" xmlns="http://www.w3.org/2000/svg" > <defs>

<filter id="f1" x="0" y="0" width="30" height="20">

</filter> </defs></svg>

http://www.w3.org/2000/svg

Example filters<svg height="110" width="110"> <defs> <filter id="f1" x="0" y="0"> <feGaussianBlur in="SourceGraphic" stdDeviation="15" /> </filter> </defs> <rect width="90" height="90" stroke="green" stroke-width="3" fill="yellow" filter="url(#f1)" /></svg>

Gradients

• SVG contains the ability to use linear and radial gradients• Also defined in defs element• Have an id defined

• Defines a number of stops andoffsets

<svg height="150" width="400"> <defs> <linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%"> <stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" /> <stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" /> </linearGradient> </defs> <ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad1)" /> </svg>

SVG

DEMO

Audio and video 5

Playing media

Media element

Supported media types

Playing media

• HTML5 defines the <audio> and <video> elements• Actual media is specified using the src attribute• Defines

• autoplay• loop• preload: how should we buffer• volume• muted• controls

• Work together with CSS• Video uses the aspect ratio from the content through

• Poster frame can be used

<video src="sample.m4v"></video><audio src="sample.mp3"></audio>

<video src="sample.m4v" poster="posterframe.png" width="100px" height="200px"></video>

Not all content is supported…

• We get support for• Video:

• WebM• H.264• OggTheora

• Audio• WebM• AAC• WAV• MP3• OggVorbis• OggOpus

• Which browser supports what depends on the weather though• Encoding in just one format is not a good idea!

Defining more than one source content file• Using the source element, we can specify multiple sources• Browser stops at first element it supports• Recommended using the MIME type here

<video width="320" height="240" controls> <source src="small.mp4" type="video/mp4"> <source src="small.ogv" type="video/ogg"> <source src="small.webm" type="video/webm"> Bad news...Your browser does not support the video tag.</video>

How about controlling playback?

• You’ll have to write some JavaScript here!• play• pause• playbackRate• currentTime• duration• buffered

var video = document.getElementById("thevideo");video.play();window.setTimeout(function () { video.pause();}, 1000);

Audio and video

DEMO

Feature detection 6

Sadly, not all browsers support all the above…• HTML5 develops fast• Browsers develop fast• Not all features work on all browsers• Sometimes they work but stop working in newer versions!

• A solution is using• Browser detection• Feature detection• Polyfills

Browser detection

• Detecting which browser is being used• Based on this, we enable or disable functionalities

• Main problem• Too many browsers• Too many versions of all these browsers

• We have to make too many assumptions about which browser supports what feature

• Still used for legacy browser/features though

Better: feature detection

• Very often used today• Checks whether a certain feature is supported• If not, disable or use alternative

if( window.addEventListener ){ // HTML that will be rendered if // addEventListener is available}else{ // HTML that will be rendered if // addEventListener is not available}

<video src="test.mp4"> <object src="test.mp4"> <a href="test.mp4"> Download the video </a> </object></video>

Modernizr

• Free library that allows feature detection• Based on the return values from Modernizr, we can downgrade gracefully

• Depending on the feature, Modernizr can provide behaviour to fill-in the missing behaviour• Not to the level of a polyfill though

• Runs a number of tests• Creates elements in memory and checks if the returned values from the

browser indicate if the feature is supported or not

• Comes with MVC projects as well if (Modernizr.canvas) { // HTML that will be rendered if the // Canvas element is available}

Polyfills

• A shim or polyfill is a block of functionality to replace a missing browser feature• For missing addEventListener, you can use a polyfill that will add this

behaviour

• Modernizr adds some polyfill behaviour• Adds support for header, footer… elements in older browsers

• Note that not everything can be fixed with polyfills!

Feature detection with Modernizr

DEMO

Geolocation 7

Geolocation

• Allows a web page to determine where we user physically is • Sometimes, by approach

• Based on the device capabilities as well• Can be “one time” or continuous • Based on• GPS• WiFi• Cell phone (triangulation)

Functions

• JavaScript API• Defines

• getCurrentPosition• watchPosition• clearWatch var watchid =

navigator.geolocation.watchPosition (successCallback, errorCallback);function successCallback(e) { // success code }function errorCallback(e) { // failure code }

navigator.geolocation.getCurrentPosition (successCallback, errorCallback);function successCallback(e) { // success code }function errorCallback(e) { // error code }

Geolocation objects

• Defines• PositionOptions

• enableHighAccuracy• timeout• maximumAge

• Position• Coordinates

• Latitude• Longitude• Altitude• Accuracy• Speed• Heading

• PositionError

navigator.geolocation.getCurrentPosition (successCallback, errorCallback, { enableHighAccuracy: true, maximumAge: 2000, timeout: 1000 });function successCallback(e) { // success code }function errorCallback(e) { // failure code }

Security

• If denied, error callback will fire with the PERMISSION_DENIED error

Geolocation

DEMO

Drag and drop 8

Drag and drop

• Common thing to do on the desktop• Add items to cart• Drag emails to folder

• Used to be possible only using JavaScript• With HTML5, a new API is included• Events• Markup attributes to make elements draggable or accept drops• DataTransfer object

Drag and drop attributes

• draggable• Can be added on every element• Can be

• true• false• auto: default to what the browser allows

• dropzone• Can be added on every element• Can be

• copy• move• link

• Not supported currently

<div draggable="true">Drag me please</div>

<div dropzone="copy"> Drop something on me please</div>

Drag and drop events

• A number of events are included• dragstart• drag• dragenter• dragleave• dragover• drop• dropend

• Can be added on the draggable element

var div = document.getElementById('draggableDiv');div.addEventListener('dragstart', doDragStart, false);function doDragStart(e) { // do something cool like opacity stuff for dragging }

DataTransfer

• All is captured in the dataTransfer object• Includes the data that is sent during the dragging• Can be set in the dragStart• Data is accessible in the drop event• Defines a getData and setData function• Format• data

var div = document.getElementById('draggableDiv');div.addEventListener('dragstart', doDragStart, false);function doDragStart(a) { a.dataTransfer.setData("text/plain", "Hello TechDays");}

Drag and drop

DEMO

Local storage 9

Several options exist

• Cookies…• Web storage• IndexedDB• File system• Other libraries exist such as store.js…

Web storage

• Web storage can be local or session-based• Comparable to cookies• Simple text files stored on the client• Limited to 4kB and maximum number of cookies• Sent to the server with every request• Can be created and manipulated from JavaScript

var expiredate = new Date();expiredate.setDate(expiredate.getDate() + 20);var cookieData= ”data” + "; expires="+ expiredate.toUTCString();document.cookie= "cookieName=" +cookieData;

Web storage

• Offers also persistent storage on the client• More storage than cookies• Easier to manipulate from code

• 2 options: • sessionStorage• localStorage• Both are implemented as a dictionary• Data is stored as strings (objects need to be converted to strings using

JSON.stringify)• Amount of available storage is dependent on the browser

• Usually around 5MB

WebStorage

• localStorage• Keeps data even if session is removed

• Closing browser has no effect on storage• Spans multiple windows and tabs

• sessionStorage• Per page per window• Separate instances of the site use different storage

Storage API

• length• clear()• getItem(key)• setItem(key, value)• removeItem(key)• key(index)• onStorage event fires

when a value is changed

var item = localStorage.getItem(“itemKey”);

localStorage.setItem(“key”, “value”);

window.addEventListener("storage", writelogs, false);function writelogs(e) { console.log(e.key); console.log(e.oldValue); console.log(e.newValue); console.log(e.url); console.log(e.storageArea);}

Local storage

DEMO

File API 10

Files

• Most languages can work with files• JavaScript couldn’t however• Changed with HTML5

• Is an asynchronous API• API defines File and Blob objects• Also defines functions to read and write files

File objects

• File API defines a number of important objects• Blob: raw, immutable data• File: a typical file representation• FileList: list of one or more File objects• FileReader: used to read file contents

• Each defines a number of properties and functions• Blob: slice(), size• File: name, lastModifiedDate

var blobClone = blob.slice(); var blobClone2 = blob.slice(0, blob.size);var blobChunk = blob.slice(0, Math.round(blob.size/2));

Accessing files

• We can access files through file input or DataTransfer (Drag and drop)• Setting multiple on the file input allows selecting more than one file

function readSelectedFiles(e) { var files = e.target.files; for (var i = 0; i < files.length; i++) { console.log(files.item(i).name); console.log(files.item(i).size); console.log(files.item(i).lastModifiedDate.toLocaleDateString()); }}document.getElementById('file').addEventListener('change', readSelectedFiles, false);

Reading files

• Once we have the files, we can read them using the FileReader• Defines readAsText, readAsDataUrl, readAsArrayBuffer…

and events such as onloadstart, onload, onerror…function readSelectedFiles(e) { var files = e.target.files; for (var i = 0; i < files.length; i++) { var reader = new FileReader(); reader.onload = (function(theFile) { return function(e) { console.log(e.target.result); }; })(files[i]); reader.readAsText(files[i]); }}document.getElementById('file').addEventListener('change', readSelectedFiles, false);

File API

DEMO

Summary

• HTML5 adds a great number of features to the language• Many, previously impossible scenarios now become possible

Thanks!

Top 10 HTML5 featuresevery developer should

knowGill Cleeren@gillcleeren

Top 10 HTML5 features

Software

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