html5 loader,jquery.html5loader
jQuery.html5Loader can preload images, html5 video and audio sources, css, scripts and text files.
This plugin needs a JSON file to get the files that must be preloaded (you can use also use a javascript object as well), and it provides an easy API to give you the the amount of file loaded in percentage.
Introduction
jQuery.html5Loader can preload images, SVGs, html5 video and audio sources, css, scripts and text files.
This plugin needs a JSON file to get the files that must be preloaded (you can use also use a javascript object as well), and it provides an easy API to give you the right amount of files loaded in percentage.
All the javascript and css files will be automatically loaded and injected into the DOM
Installation
$ bower install jquery.html5loader
Features
smart: it loads just the sources supported by the client running the script.
flexible: it returns the current percentage and the object/element loaded, so you could be free to show this info as you prefer
fun: inside the package you could find some preloading animation examples, customizable and ready to use
Demos
Production websites using jQuery.html5loader
USAGE
1 Create a JSON file like this, containing all the files you need to preload ( size in bytes ):
{
"files": [
{
"type":"SCRIPT",
"source":"../path/to/your/script.js",
"size":4.096,
"stopExecution":true
},
{
"type":"SCRIPT",
"source":"../path/to/your/script.js",
"size":4.096,
"stopExecution":false
},
{
"type":"IMAGE",
"source":"../path/to/your/image.jpg",
"size":620
},
{
"type": "CSS",
"source": "../files/test.css",
"size": 16.819
},
{
"type":"TEXT",
"source":"../path/to/your/text.txt",
"size":44
},
{
"source": {
"svg": "../files/yin-yang.svg",
"fallback": "../files/yin-yang.jpg"
},
"type": "IMAGE",
"size": 2338
},
{
"type":"VIDEO",
"sources": {
"webm":{
"source":"../path/to/your/video.webm",
"size":5054.976
},
"ogg":{
"source":"../path/to/your/video.ogg",
"size":2932.736
},
"h264":{
"source":"../path/to/your/video.mp4",
"size":9285.632
},
"vp9": {
"source":"../path/to/your/video.webm",
"size":9285.632
}
}
}
},
{
"type":"AUDIO",
"sources": {
"mp3":{
"source":"../path/to/your/audio.mp3",
"size":9285.632
},
"ogg":{
"source":"../path/to/your/audio.ogg",
"size":2089.688
},
"opus": {
"source": "../path/to/your/audio.opus",
"size":2000.20
},
"wav": {
"source": "../path/to/your/audio.wav",
"size":2000.20
},
"m4a": {
"source": "../path/to/your/audio.m4a",
"size":2000.20
}
}
}
]
}
2 Import the plugin into your page:
3 Initialize the plugin setting the callback functions:
$.html5Loader({
filesToLoad: '../js/files.json', // this could be a JSON or simply a javascript object
onBeforeLoad: function () {},
onComplete: function () {},
onElementLoaded: function ( obj, elm) { },
onUpdate: function ( percentage ) {}
});
API
Methods
stopExecution: default false, do not execute the javascript files when they'll be preloaded, this option could be overridden into the json per each javascript file
mediaBufferSizeToPreload: default 0.2, decide the the buffer size before considering the media preloaded
forceMediaPreload: default true, let the browser decide when the media file has been buffered enough to be played by listening the canplaythrough event
onBeforeLoad It is triggered right before the plugin starts loading all the files
onComplete It is triggered when the plugin finishes to load all the sources
onMediaError This function is called in case there's an error during the preloadingobj original object passed to the plugin
elm html output (for type "SCRIPT" and "TEXT" this value is just a string)
stopExecution (false by default) : default behavior for all the script files, they won't execute when loaded. This behavior can be changed by each script object passed to the plugin
onElementLoaded It is triggered anytime a new element of your files list gets loaded, (ATTENTION IF AN ELEMENT IS NOT SUPPORTED IT WILL NEVER PASS TROUGH THIS FUNCTION).obj original object passed to the plugin
elm html output (for type "SCRIPT" and "TEXT" this value is just a string)
onUpdate it is triggered anytime new bytes are loadedpercentage the percentage currently loaded
Loading Segments
It is also possible to load groups of files in sequence by wrapping them in arrays. This could be handy if you need need to preload components with dependencies. e.g Backbone's dependence on underscore.
{
"files": [
[
{
"type":"SCRIPT",
"source":"../path/to/underscore.js",
"size":13.9
}
],
[
{
"source": "../path/to/backbone.js",
"type": "SCRIPT",
"size": 37.5
},
{
"source": "../path/to/three.js",
"type": "SCRIPT",
"size": 150.3
}
]
]
}
Loading SVGs
You can also load SVG files providing a fallback image. jQuery.html5Loader will detect automatically if the device supports the SVGs otherwise it will just preload the fallback image.
"files":[
{
"source": {
"svg": "../files/yin-yang.svg",
"fallback": "../files/yin-yang.jpg"
},
"type": "IMAGE",
"size": 2338
}
]
KNOWN ISSUES
Internet Explorer 9 and 10 do not return any value using the method canPlayType on a video or audio element ( http://modernizr.com/docs/#audio ). For these browsers we don't preload any HTML5 media format
on mobile devices and on the iPad we cannot load any video or audio element because these devices can't preload those kind of elements until the user start dealing with them
TODO List
Write down a valid crossbrowser unit test
CHANGELOG
v1.8.0
added: SVGs preloading support
added: segments preloading
updated: the nprogress example
v1.7.0
added: better tablet detection tests
added: grunt
bugfix: skip media elements loading on mobile/tablet devices
v1.6.9
added: mediaBufferSizeToPreload option
added: forceMediaPreload option
v1.6.8
small refactor
added: new media file codecs tests
video: vp9
audio: opus, wav, m4a
added: stopExecution option
added: stopExecution option via json
added: nprogress demo
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