HTML5中5个简单实用的API（第二篇，含全屏、可见

// Find the right method, call on correct element
function launchFullScreen(element) {
if(element.requestFullScreen) {
element.requestFullScreen();
} else if(element.mozRequestFullScreen) {
element.mozRequestFullScreen();
} else if(element.webkitRequestFullScreen) {
element.webkitRequestFullScreen();
}
}</p><p>// Launch fullscreen for browsers that support it!
launchFullScreen(document.documentElement); // the whole page
launchFullScreen(document.getElementById("videoElement")); // any individual element

// Adapted slightly from Sam Dutton
// Set name of hidden property and visibility change event
// since some browsers only offer vendor-prefixed support
var hidden, state, visibilityChange;
if (typeof document.hidden !== "undefined") {
hidden = "hidden";
visibilityChange = "visibilitychange";
state = "visibilityState";
} else if (typeof document.mozHidden !== "undefined") {
hidden = "mozHidden";
visibilityChange = "mozvisibilitychange";
state = "mozVisibilityState";
} else if (typeof document.msHidden !== "undefined") {
hidden = "msHidden";
visibilityChange = "msvisibilitychange";
state = "msVisibilityState";
} else if (typeof document.webkitHidden !== "undefined") {
hidden = "webkitHidden";
visibilityChange = "webkitvisibilitychange";
state = "webkitVisibilityState";
}</p><p>// Add a listener that constantly changes the title
document.addEventListener(visibilityChange, function(e) {
// Start or stop processing depending on state</p><p>}, false);

// Put event listeners into place
window.addEventListener("DOMContentLoaded", function() {
// Grab elements, create settings, etc.
var canvas = document.getElementById("canvas"),
context = canvas.getContext("2d"),
video = document.getElementById("video"),
videoObj = { "video": true },
errBack = function(error) {
console.log("Video capture error: ", error.code);
};</p><p> // Put video listeners into place
if(navigator.getUserMedia) { // Standard
navigator.getUserMedia(videoObj, function(stream) {
video.src = stream;
video.play();
}, errBack);
} else if(navigator.webkitGetUserMedia) { // WebKit-prefixed
navigator.webkitGetUserMedia(videoObj, function(stream){
video.src = window.webkitURL.createObjectURL(stream);
video.play();
}, errBack);
}
}, false);

// Get the battery!
var battery = navigator.battery || navigator.webkitBattery || navigator.mozBattery;</p><p>// A few useful battery properties
console.warn("Battery charging: ", battery.charging); // true
console.warn("Battery level: ", battery.level); // 0.58
console.warn("Battery discharging time: ", battery.dischargingTime);</p><p>// Add a few event listeners
battery.addEventListener("chargingchange", function(e) {
console.warn("Battery charge change: ", battery.charging);
}, false);

<!-- 预加载一个页面 -->
<link rel="prefetch" href="http://www.jb51.net/link-prefetch/" /></p><p><!-- 预加载一个图片 -->
<link rel="prefetch" href="http://www.jb51.net/wordpress/wp-content/themes/webhek2/images/follow-us.jpg?067588" />