HTML5 Web Storage - What is HTML5 Web Storage? - localStorage and sessionStorage - localStorage Object - sessionStorage Object

HTML5 web storage, a better local storage than cookies.

What is HTML5 Web Storage?

With HTML5, web pages can store data locally within the user's browser.

Earlier, this was done with cookies. However, Web Storage is more secure and faster. The data is not included with every server request, but used ONLY when asked for. It is also possible to store large amounts of data, without affecting the website's performance.

The data is stored in key/value pairs, and a web page can only access data stored by itself.

Browser Support

Web storage is supported in Internet Explorer 8+, Firefox, Opera, Chrome, and Safari.

Note: Internet Explorer 7 and earlier versions, do not support web storage.

localStorage and sessionStorage 

There are two new objects for storing data on the client:

• localStorage - stores data with no expiration date
• sessionStorage - stores data for one session

Before using web storage, check browser support for localStorage and sessionStorage:

if(typeof(Storage)!=="undefined")
  {
  // Yes! localStorage and sessionStorage support!
  // Some code.....
  }
else
  {
  // Sorry! No web storage support..
  }

The localStorage Object

The localStorage object stores the data with no expiration date. The data will not be deleted when the browser is closed, and will be available the next day, week, or year.

Example:

localStorage.lastname="Smith";
document.getElementById("result").innerHTML="Last name: "
+ localStorage.lastname;

Example explained:

• Create a localStorage key/value pair with key="lastname" and value="Smith"
• Retrieve the value of the "lastname" key and insert it into the element with id="result"

Tip: Key/value pairs are always stored as strings. Remember to convert them to another format when needed.

The following example counts the number of times a user has clicked a button. In this code the value string is converted to a number to be able to increase the counter:

Example:

if (localStorage.clickcount)
  {
  localStorage.clickcount=Number(localStorage.clickcount)+1;
  }
else
  {
  localStorage.clickcount=1;
  }
document.getElementById("result").innerHTML="You have clicked the button " + localStorage.clickcount + " time(s).";

The sessionStorage Object

The sessionStorage object is equal to the localStorage object, except that it stores the data for only one session. The data is deleted when the user closes the browser window.

The following example counts the number of times a user has clicked a button, in the current session:

Example:

if (sessionStorage.clickcount)
  {
  sessionStorage.clickcount=Number(sessionStorage.clickcount)+1;
  }
else
  {
  sessionStorage.clickcount=1;
  }
document.getElementById("result").innerHTML="You have clicked the button " + sessionStorage.clickcount + " time(s) in this session.";

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HTML5 Geolocation - Locate the User's Position - Handling Errors and Rejections

Locate the User's Position

The HTML5 Geolocation API is used to get the geographical position of a user.

Since this can compromise user privacy, the position is not available unless the user approves it.

Browser Support

Internet Explorer 9, Firefox, Chrome, Safari and Opera support Geolocation.
Note: Geolocation is much more accurate for devices with GPS, like iPhone

HTML5 - Using Geolocation

Use the getCurrentPosition() method to get the user's position.
The example below is a simple Geolocation example returning the latitude and longitude of the user's position:

Example:

<script>
var x=document.getElementById("demo");
function getLocation()
  {
  if (navigator.geolocation)
    {
    navigator.geolocation.getCurrentPosition(showPosition);
    }
  else{x.innerHTML="Geolocation is not supported by this browser.";}
  }
function showPosition(position)
  {
  x.innerHTML="Latitude: " + position.coords.latitude + 
  "<br />Longitude: " + position.coords.longitude; 
  }
</script>

Example explained:

• Check if Geolocation is supported
• If supported, run the getCurrentPosition() method. If not, display a message to the user
• If the getCurrentPosition() method is successful, it returns a coordinates object to the function specified in the parameter ( showPosition )
• The showPosition() function gets the displays the Latitude and Longitude

The example above is a very basic Geolocation script, with no error handling.

Handling Errors and Rejections

The second parameter of the getCurrentPosition() method is used to handle errors. It specifies a function to run if it fails to get the user's location:

function showError(error)
  {
  switch(error.code) 
    {
    case error.PERMISSION_DENIED:
      x.innerHTML="User denied the request for Geolocation."
      break;
    case error.POSITION_UNAVAILABLE:
      x.innerHTML="Location information is unavailable."
      break;
    case error.TIMEOUT:
      x.innerHTML="The request to get user location timed out."
      break;
    case error.UNKNOWN_ERROR:
      x.innerHTML="An unknown error occurred."
      break;
    }
  }


Error Codes:

• Permission denied - The user did not allow Geolocation
• Position unavailable - It is not possible to get the current location
•  Timeout - The operation timed out

Displaying the Result in a Map

To display the result in a map, you need access to a map service that can use latitude and longitude, like Google Maps:

function showPosition(position)
{
var latlon=position.coords.latitude+","+position.coords.longitude;

var img_url="http://maps.googleapis.com/maps/api/staticmap?center="
+latlon+"&zoom=14&size=400x300&sensor=false";

document.getElementById("mapholder").innerHTML="<img src='"+img_url+"' />";
}

In the example above we use the returned latitude and longitude data to show the location in a Google map (using a static image).
How to use a script to show an interactive map with a marker, zoom and drag options.

Location-specific Information

This page demonstrated how to show a user's position on a map. However, Geolocation is also very useful for location-specific information.
Examples:

• Up-to-date local information
• Showing Points-of-interest near the user
• Turn-by-turn navigation (GPS)

The getCurrentPosition() Method - Return Data

The getCurrentPosition() method returns an object if it is successful. The latitude, longitude and accuracy properties are always returned. The other properties below are returned if available.

Property	Description
coords.latitude	The latitude as a decimal number
coords.longitude	The longitude as a decimal number
coords.accuracy	The accuracy of position
coords.altitude	The altitude in meters above the mean sea level
coords.altitudeAccuracy	The altitude accuracy of position
coords.heading	The heading as degrees clockwise from North
coords.speed	The speed in meters per second
timestamp	The date/time of the response

Geolocation object - Other interesting Methods

watchPosition() - Returns the current position of the user and continues to return updated position as the user moves (like the GPS in a car).
clearWatch() - Stops the watchPosition() method.
The example below shows the watchPosition() method. You need an accurate GPS device to test this (like iPhone):

Example:

<script>
var x=document.getElementById("demo");
function getLocation()
  {
  if (navigator.geolocation)
    {
    navigator.geolocation.watchPosition(showPosition);
    }
  else{x.innerHTML="Geolocation is not supported by this browser.";}
  }
function showPosition(position)
  {
  x.innerHTML="Latitude: " + position.coords.latitude + 
  "<br />Longitude: " + position.coords.longitude; 
  }
</script>

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HTML5 Canvas vs. SVG - SVG - Canvas - Comparison of Canvas and SVG

Both canvas and SVG allow you to create graphics inside the browser, but they are fundamentally different.

SVG

SVG is a language for describing 2D graphics in XML.

SVG is XML based, which means that every element is available within the SVG DOM. You can attach JavaScript event handlers for an element.

In SVG, each drawn shape is remembered as an object. If attributes of an SVG object are changed, the browser can automatically re-render the shape.

Canvas

Canvas draws 2D graphics, on the fly (with a JavaScript).

Canvas is rendered pixel by pixel.

In canvas, once the graphic is drawn, it is forgotten by the browser. If its position should be changed, the entire scene needs to be redrawn, including any objects that might have been covered by the graphic.

Comparison of Canvas and SVG

The table below shows some important differences between canvas and SVG.

Canvas	SVG
Resolution dependent No support for event handlers Poor text rendering capabilities You can save the resulting image as .png or .jpg Best suited for graphic-intensive games where many objects are redrawn frequently	Resolution independent Support for event handlers Best suited for applications with large rendering areas (Google Maps) Slow rendering if complex (anything that uses the DOM a lot will be slow) Not suited for game applications

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HTML5 Inline SVG - What is SVG? - SVG Advantag - Browser Supportes - Embed SVG Directly Into HTML Pages - Example - SVG Elements

What is SVG?

• SVG stands for Scalable Vector Graphics
• SVG is used to define vector-based graphics for the Web
• SVG defines the graphics in XML format
• SVG graphics do NOT lose any quality if they are zoomed or resized
• Every element and every attribute in SVG files can be animated
• SVG is a W3C recommendation

SVG Advantages

Advantages of using SVG over other image formats (like JPEG and GIF) are:

• SVG images can be created and edited with any text editor
• SVG images can be searched, indexed, scripted, and compressed
• SVG images are scalable
• SVG images can be printed with high quality at any resolution
• SVG images are zoomable (and the image can be zoomed without degradation)

Browser Support

Internet Explorer 9, Firefox, Opera, Chrome, and Safari support inline SVG.

Embed SVG Directly Into HTML Pages

In HTML5, you can embed SVG elements directly into your HTML page:

Example:

<!DOCTYPE html>
<html>
<body>

<svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="190">
  <polygon points="100,10 40,180 190,60 10,60 160,180"
  style="fill:lime;stroke:purple;stroke-width:5;fill-rule:evenodd;" />
</svg>

</body>
</html>

Result:

SVG Reference:

SVG Elements

Element	Description	Attributes
<a>	Creates a link around SVG elements	xlink:show xlink:actuate xlink:href target
<altGlyph>	Provides control over the glyphs used to render particular character data	x y dx dy rotate glyphRef format xlink:href
<altGlyphDef>	Defines a substitution set for glyphs	id
<altGlyphItem>	Defines a candidate set of glyph substitutions	id
<animate>	Defines how an attribute of an element changes over time	attributeName="the name of the target attribute" from="the starting value" to="the ending value" dur="the duration" repeatCount="the number of time the animation will take place"
<animateColor>	Defines a color transformation over time	by="a relative offset value" from="the starting value" to="the ending value"
<animateMotion>	Causes a referenced element to move along a motion path	calcMode="the interpolation mode for the animation. Can be 'discrete', 'linear', 'paced', 'spline'" path="the motion path" keyPoints="how far along the motion path the object shall move at the moment in time" rotate="applies a rotation transformation" xlink:href="an URI reference to the <path> element which defines the motion path"
<animateTransform>	Animates a transformation attribute on a target element, thereby allowing animations to control translation, scaling, rotation and/or skewing	by="a relative offset value" from="the starting value" to="the ending value" type="the type of transformation which is to have its values change over time. Can be 'translate', 'scale', 'rotate', 'skewX', 'skewY'"
<circle>	Defines a circle	cx="the x-axis center of the circle" cy="the y-axis center of the circle" r="The circle's radius". Required. + presentation attributes: Color, FillStroke, Graphics
<clipPath>	Clipping is about hiding what normally would be drawn. The stencil which defines what is and what isn't drawn is called a clipping path	clip-path="the referenced clipping path is intersected with the referencing clipping path" clipPathUnits="'userSpaceOnUse' or 'objectBoundingBox'. The second value makes units of children a fraction of the object bounding box which uses the mask (default: 'userSpaceOnUse')"
<color-profile>	Specifies a color profile description (when the document is styled using CSS)	local="the unique ID for a locally stored color profile" name="" rendering-intent="auto|perceptual|relative-colorimetric|saturation|absolute-colorimetric" xlink:href="the URI of an ICC profile resource"
<cursor>	Defines a platform-independent custom cursor	x="the x-axis top-left corner of the cursor (default is 0)" y="the y-axis top-left corner of the cursor (default is 0)" xlink:href="the URI of the image to use as the cursor
<defs>	A container for referenced elements
<desc>	A text-only description for container elements or graphic elements in SVG (user agents may display the text as a tooltip)
<ellipse>	Defines an ellipse	cx="the x-axis center of the ellipse" cy="the y-axis center of the ellipse" rx="the length of the ellipse's radius along the x-axis". Required. ry="the length of the ellipse's radius along the y-axis". Required. + presentation attributes: Color, FillStroke, Graphics
<feBlend>	Composes two objects together according to a certain blending mode	mode="the image blending modes: normal|multiply|screen|darken|lighten" in="identifies input for the given filter primitive: SourceGraphic | SourceAlpha | BackgroundImage | BackgroundAlpha | FillPaint | StrokePaint | <filter-primitive-reference>" in2="the second input image to the blending operation"
feColorMatrix	SVG filter. Applies a matrix transformation
feComponentTransfer	SVG filter. Performs component-wise remapping of data
feComposite	SVG filter.
feConvolveMatrix	SVG filter.
feDiffuseLighting	SVG filter.
feDisplacementMap	SVG filter.
feDistantLight	SVG filter. Defines a light source
feFlood	SVG filter.
feFuncA	SVG filter. Sub-element to feComponentTransfer
feFuncB	SVG filter. Sub-element to feComponentTransfer
feFuncG	SVG filter. Sub-element to feComponentTransfer
feFuncR	SVG filter. Sub-element to feComponentTransfer
feGaussianBlur	SVG filter. Performs a Gaussian blur on the image
feImage	SVG filter.
feMerge	SVG filter. Creates image layers on top of each other
feMergeNode	SVG filter. Sub-element to feMerge
feMorphology	SVG filter. Performs a "fattening" or "thinning" on a source graphic
feOffset	SVG filter. Moves an image relative to its current position
fePointLight	SVG filter.
feSpecularLighting	SVG filter.
feSpotLight	SVG filter.
feTile	SVG filter.
feTurbulence	SVG filter.
filter	Container for filter effects
font	Defines a font
font-face	Describes the characteristics of a font
font-face-format
font-face-name
font-face-src
font-face-uri
foreignObject
<g>	Used to group together elements	id="the name of the group" fill="the fill color for the group" opacity="the opacity for the group" + presentation attributes: All
glyph	Defines the graphics for a given glyph
glyphRef	Defines a possible glyph to use
hkern
<image>	Defines an image	x="the x-axis top-left corner of the image" y="the y-axis top-left corner of the image" width="the width of the image". Required. height="the height of the image". Required. xlink:href="the path to the image". Required. + presentation attributes: Color, Graphics, Images, Viewports
<line>	Defines a line	x1="the x start point of the line" y1="the y start point of the line" x2="the x end point of the line" y2="the y end point of the line" + presentation attributes: Color, FillStroke, Graphics, Markers
<linearGradient>	Defines a linear gradient. Linear gradients fill the object by using a vector, and can be defined as horizontal, vertical or angular gradients.	id="the unique id used to reference this pattern. Required to reference it" gradientUnits="'userSpaceOnUse' or 'objectBoundingBox'. Use the view box or object to determine relative position of vector points. (Default 'objectBoundingBox')" gradientTransform="the transformation to apply to the gradient" x1="the x start point of the gradient vector (number or % - 0% is default)" y1="the y start point of the gradient vector. (0% default)" x2="the x end point of the gradient vector. (100% default)" y2="the y end point of the gradient vector. (0% default)" spreadMethod="'pad' or 'reflect' or 'repeat'" xlink:href="reference to another gradient whose attribute values are used as defaults and stops included. Recursive"
<marker>	Markers can be placed on the vertices of lines, polylines, polygons and paths. These elements can use the marker attributes "marker-start", "marker-mid" and "marker-end"' which inherit by default or can be set to 'none' or the URI of a defined marker. You must first define the marker before you can reference it via its URI. Any kind of shape can be put inside marker. They are drawn on top of the element they are attached to	markerUnits="'strokeWidth' or 'userSpaceOnUse'. If 'strokeWidth' is used then one unit equals one stroke width. Otherwise, the marker does not scale and uses the the same view units as the referencing element (default 'strokeWidth')" refx="the position where the marker connects with the vertex (default 0)" refy="the position where the marker connects with the vertex (default 0)" orient="'auto' or an angle to always show the marker at. 'auto' will compute an angle that makes the x-axis a tangent of the vertex (default 0)" markerWidth="the width of the marker (default 3)" markerHeight="the height of the marker (default 3)" viewBox="the points "seen" in this SVG drawing area. 4 values separated by white space or commas. (min x, min y, width, height)" + presentation attributes: All
<mask>	Masking is a combination of opacity values and clipping. Like clipping you can use shapes, text or paths to define sections of the mask. The default state of a mask is fully transparent which is the opposite of clipping plane. The graphics in a mask sets how opaque portions of the mask are	maskUnits="'userSpaceOnUse' or 'objectBoundingBox'. Set whether the clipping plane is relative the full view port or object (default: 'objectBoundingBox')" maskContentUnits="Use the second with percentages to make mask graphic positions relative the object. 'userSpaceOnUse' or 'objectBoundingBox' (default: 'userSpaceOnUse')" x="the clipping plane of the mask (default: -10%)" y="the clipping plane of the mask (default: -10%)" width="the clipping plane of the mask (default: 120%)" height="the clipping plane of the mask (default: 120%)"
metadata	Specifies metadata
missing-glyph
mpath
<path>	Defines a path	d="a set of commands which define the path" pathLength="If present, the path will be scaled so that the computed path length of the points equals this value" transform="a list of transformations" + presentation attributes: Color, FillStroke, Graphics, Markers
<pattern>	Defines the coordinates you want the view to show and the size of the view. Then you add shapes into your pattern. The pattern repeats when an edge of the view box (viewing area) is hit	id="the unique id used to reference this pattern." Required. patternUnits="'userSpaceOnUse' or 'objectBoundingBox'. The second value makes units of x, y, width, height a fraction (or %) of the object bounding box which uses the pattern." patternContentUnits="'userSpaceOnUse' or 'objectBoundingBox'" patternTransform="allows the whole pattern to be transformed" x="pattern's offset from the top-left corner (default 0)" y="pattern's offset from the top-left corner. (default 0)" width="the width of the pattern tile (default 100%)" height="the height of the pattern tile (default 100%)" viewBox="the points "seen" in this SVG drawing area. 4 values separated by white space or commas. (min x, min y, width, height)" xlink:href="reference to another pattern whose attribute values are used as defaults and any children are inherited. Recursive"
<polygon>	Defines a graphic that contains at least three sides	points="the points of the polygon. The total number of points must be even". Required. fill-rule="part of the FillStroke presentation attributes" + presentation attributes: Color, FillStroke, Graphics, Markers
<polyline>	Defines any shape that consists of only straight lines	points="the points on the polyline". Required. + presentation attributes: Color, FillStroke, Graphics, Markers
<radialGradient>	Defines a radial gradient. Radial gradients are created by taking a circle and smoothly changing values between gradient stops from the focus point to the outside radius.	gradientUnits="'userSpaceOnUse' or 'objectBoundingBox'. Use the view box or object to determine relative position of vector points. (Default 'objectBoundingBox')" gradientTransform="the transformation to apply to the gradient" cx="the center point of the gradient (number or % - 50% is default)" cy="the center point of the gradient. (50% default)" r="the radius of the gradient. (50% default)" fx="the focus point of the gradient. (0% default)" fy="The focus point of the gradient. (0% default)" spreadMethod="'pad' or 'reflect' or 'repeat'" xlink:href="Reference to another gradient whose attribute values are used as defaults and stops included. Recursive"
<rect>	Defines a rectangle	x="the x-axis top-left corner of the rectangle" y="the y-axis top-left corner of the rectangle" rx="the x-axis radius (to round the element)" ry="the y-axis radius (to round the element)" width="the width of the rectangle". Required. height="the height of the rectangle" Required. + presentation attributes: Color, FillStroke, Graphics
script	Container for scripts (e.g., ECMAScript)
set	Sets the value of an attribute for a specified duration
<stop>	The stops for a gradient	offset="the offset for this stop (0 to 1/0% to 100%)". Required. stop-color="the color of this stop" stop-opacity="the opacity of this stop (0 to 1)"
style	Allows style sheets to be embedded directly within SVG content
<svg>	Creates an SVG document fragment	x="top left corner when embedded (default 0)" y="top left corner when embedded (default 0)" width="the width of the svg fragment (default 100%)" height="the height of the svg fragment (default 100%)" viewBox="the points "seen" in this SVG drawing area. 4 values separated by white space or commas. (min x, min y, width, height)" preserveAspectRatio="'none' or any of the 9 combinations of 'xVALYVAL' where VAL is 'min', 'mid' or 'max'. (default xMidYMid)" zoomAndPan="'magnify' or 'disable'. Magnify option allows users to pan and zoom your file (default magnify)" xml="outermost <svg> element needs to setup SVG and its namespace: xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve"" + presentation attributes: All
switch
symbol
<text>	Defines a text	x="a list of x-axis positions. The nth x-axis position is given to the nth character in the text. If there are additional characters after the positions run out they are placed after the last character. 0 is default" y="a list of y-axis positions. (see x). 0 is default" dx="a list of lengths which moves the characters relative to the absolute position of the last glyph drawn. (see x)" dy="a list of lengths which moves the characters relative to the absolute position of the last glyph drawn. (see x)" rotate="a list of rotations. The nth rotation is performed on the nth character. Additional characters are NOT given the last rotation value" textLength="a target length for the text that the SVG viewer will attempt to display the text between by adjusting the spacing and/or the glyphs. (default: The text's normal length)" lengthAdjust="tells the viewer what to adjust to try to accomplish rendering the text if the length is specified. The two values are 'spacing' and 'spacingAndGlyphs'" + presentation attributes: Color, FillStroke, Graphics, FontSpecification, TextContentElements
textPath
title	A text-only description for elements in SVG - not displayed as part of the graphics. User agents may display the text as a tooltip
<tref>	References any <text> element in the SVG document and reuse it	Identical to the <text> element
<tspan>	Identical to the <text> element but can be nested inside text tags and inside itself	Identical to the <text> element + in addition: xlink:href="Reference to a <text> element"
<use>	Uses a URI to reference a <g>, <svg> or other graphical element with a unique id attribute and replicate it. The copy is only a reference to the original so only the original exists in the document. Any change to the original effects all copies.	x="the x-axis top-left corner of the cloned element" y="the y-axis top-left corner of the cloned element" width="the width of the cloned element" height="the height of the cloned element" xlink:href="a URI reference to the cloned element" + presentation attributes: All
view
vkern

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HTML5 Drag and Drop - Drag and Drop

Drag and Drop

Drag and drop is a very common feature. It is when you "grab" an object and drag it to a different location.
In HTML5, drag and drop is part of the standard, and any element can be draggable.

Browser Support

Internet Explorer 9, Firefox, Opera 12, Chrome, and Safari 5 support drag and drop.
Note: Drag and drop does not work in Safari 5.1.2.

HTML5 Drag and Drop Example

The example below is a simple drag and drop example:

<!DOCTYPE HTML> <html> <head> <script type="text/javascript"> function allowDrop(ev) { ev.preventDefault(); } function drag(ev) { ev.dataTransfer.setData("Text",ev.target.id); } function drop(ev) { ev.preventDefault(); var data=ev.dataTransfer.getData("Text"); ev.target.appendChild(document.getElementById(data)); } </script> </head> <body> <div id="div1" ondrop="drop(event)" ondragover="allowDrop(event)"></div> <img id="drag1" src="img_logo.gif" draggable="true" ondragstart="drag(event)" width="336" height="69" /> </body> </html>

It might seem complicated, but lets go through all the different parts of a drag and drop event.

Make an Element Draggable

First of all: To make an element draggable, set the draggable attribute to true:

<img draggable="true" />

What to Drag - ondragstart and setData()

Then, specify what should happen when the element is dragged.
In the example above, the ondragstart attribute calls a function, drag(event), that specifies what data to be dragged.
The dataTransfer.setData() method sets the data type and the value of the dragged data:

function drag(ev) { ev.dataTransfer.setData("Text",ev.target.id); }

Where to Drop - ondragover

The ondragover event specifies where the dragged data can be dropped.
By default, data/elements cannot be dropped in other elements. To allow a drop, we must prevent the default handling of the element.
This is done by calling the event.preventDefault() method for the ondragover event:

event.preventDefault()

Do the Drop - ondrop

When the dragged data is dropped, a drop event occurs.
In the example above, the ondrop attribute calls a function, drop(event):

function drop(ev) { ev.preventDefault(); var data=ev.dataTransfer.getData("Text"); ev.target.appendChild(document.getElementById(data)); }

Code explained:

• Call preventDefault() to prevent the browser default handling of the data (default is open as link on drop)
• Get the dragged data with the dataTransfer.getData("Text") method. This method will return any data that was set to the same type in the setData() method
• The dragged data is the id of the dragged element ("drag1")
• Append the dragged element into the drop element

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HTML5 Audio - Audio on the Web

Audio on the Web

Until now, there has not been a standard for playing audio files on a web page.
Today, most audio files are played through a plug-in (like flash). However, different browsers may have different plug-ins.
HTML5 defines a new element which specifies a standard way to embed an audio file on a web page: the <audio> element.

Browser Support

Internet Explorer 9, Firefox, Opera, Chrome, and Safari support the <audio> element.
Note: Internet Explorer 8 and earlier versions, do not support the <audio> element.

HTML5 Audio - How It Works

To play an audio file in HTML5, this is all you need:
Example:
<audio controls="controls">
  <source src="song.ogg" type="audio/ogg" />
  <source src="song.mp3" type="audio/mpeg" />
  Your browser does not support the audio element.
</audio> 
The control attribute adds audio controls, like play, pause, and volume.
You should also insert text content between the <audio> and </audio> tags for browsers that do not support the <audio> element.
The <audio> element allows multiple <source> elements. <source> elements can link to different audio files. The browser will use the first recognized format.

Audio Formats and Browser Support

Currently, there are 3 supported file formats for the <audio> element: MP3, Wav, and Ogg:

Browser	MP3	Wav	Ogg
Internet Explorer 9	YES	NO	NO
Firefox 4.0	NO	YES	YES
Google Chrome 6	YES	YES	YES
Apple Safari 5	YES	YES	NO
Opera 10.6	NO	YES	YES

HTML5 Audio Tags

Tag	Description
<audio>	Defines sound content
<source>	Defines multiple media resources for media elements, such as <video> and <audio>

 

 

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HTML5 Video DOM

HTML5 <video> - Take Control Using the DOM

The HTML5 <video> element also has methods, properties, and events.

There are methods for playing, pausing, and loading, for example. There are properties (e.g. duration, volume, seeking) that you can read or set. There are also DOM events that can notify you, for example, when the <video> element begins to play, is paused, is ended, etc.

The examples below illustrate, in a simple way, how to address a <video> element, read and set properties, and call methods.

Example:

<!DOCTYPE html> 
<html> 
<body> 


<div style="text-align:center"> 
  <button onclick="playPause()">Play/Pause</button> 
  <button onclick="makeBig()">Big</button>
  <button onclick="makeSmall()">Small</button>
  <button onclick="makeNormal()">Normal</button>
  <br /> 
  <video id="video1" width="420">
    <source src="mov_bbb.mp4" type="video/mp4" />
    <source src="mov_bbb.ogg" type="video/ogg" />
    Your browser does not support HTML5 video.
  </video>
</div> 


<script type="text/javascript"> 
var myVideo=document.getElementById("video1"); 


function playPause()
{ 
if (myVideo.paused) 
  myVideo.play(); 
else 
  myVideo.pause(); 
} 


function makeBig()
{ 
myVideo.width=560; 
} 


function makeSmall()
{ 
myVideo.width=320; 
} 


function makeNormal()
{ 
myVideo.width=420; 
} 
</script> 


<p>Video courtesy of <a href="http://www.bigbuckbunny.org/" target="_blank">Big Buck Bunny</a>.</p>
</body> 
</html>

HTML5 <video> - Methods, Properties, and Events

The table below lists the video methods, properties, and events supported by most browsers:

Methods	Properties	Events
play()	currentSrc	play
pause()	currentTime	pause
load()	videoWidth	progress
canPlayType	videoHeight	error
	duration	timeupdate
	ended	ended
	error	abort
	paused	empty
	muted	emptied
	seeking	waiting
	volume	loadedmetadata
	height
	width

Note: Of the video properties, only videoWidth and videoHeight are immediately available. The other properties are available after the video's meta data has loaded.

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HTML5 VIDEO

Many modern websites show videos. HTML5 provides a standard for showing them.

Video on the Web

Until now, there has not been a standard for showing a video/movie on a web page.

Today, most videos are shown through a plug-in (like flash). However, different browsers may have different plug-ins.

HTML5 defines a new element which specifies a standard way to embed a video/movie on a web page: the <video> element.

Browser Support

Internet Explorer 9, Firefox, Opera, Chrome, and Safari support the <video> element.

Note: Internet Explorer 8 and earlier versions, do not support the <video> element.

HTML5 Video - How It Works

To show a video in HTML5, this is all you need:
Example:


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



The control attribute adds video controls, like play, pause, and volume.
It is also a good idea to always include width and height attributes. If height and width are set, the space required for the video is reserved when the page is loaded. However, without these attributes, the browser does not know the size of the video, and cannot reserve the appropriate space to it. The effect will be that the page layout will change during loading (while the video loads).
You should also insert text content between the <video> and </video> tags for browsers that do not support the <video> element.
The <video> element allows multiple <source> elements. <source> elements can link to different video files. The browser will use the first recognized format.

Video Formats and Browser Support

Currently, there are 3 supported video formats for the <video> element: MP4, WebM, and Ogg:

Browser	MP4	WebM	Ogg
Internet Explorer 9	YES	NO	NO
Firefox 4.0	NO	YES	YES
Google Chrome 6	YES	YES	YES
Apple Safari 5	YES	NO	NO
Opera 10.6	NO	YES	YES

• MP4 = MPEG 4 files with H264 video codec and AAC audio codec
• WebM = WebM files with VP8 video codec and Vorbis audio codec
• Ogg = Ogg files with Theora video codec and Vorbis audio codec

HTML5 Video Tags

Tag	Description
<video>	Defines a video or movie
<source>	Defines multiple media resources for media elements, such as <video> and <audio>
<track>	Defines text tracks in mediaplayers

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