你可能不知道的 5 个强大的 HTML5 API

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1. 全屏API(Fullscreen API)

该API允许开发开发者以编程的方式将Web应用程序全屏运行,使Web应用程序更像本地应用程序。

// 找到适合浏览器的全屏方法  function launchFullScreen(element) {    if(element.requestFullScreen) {      element.requestFullScreen();    } else if(element.mozRequestFullScreen) {      element.mozRequestFullScreen();    } else if(element.webkitRequestFullScreen) {      element.webkitRequestFullScreen();    }  }    // 启动全屏模式  launchFullScreen(document.documentElement); // the whole page  launchFullScreen(document.getElementById("videoElement")); // any individual element  


2. 页面可见性API(Page Visibility API)

该API可以用来检测页面对于用户的可见性,即返回用户当前浏览的页面或标签的状态变化。

// 设置隐藏属性和可见改变事件的名称,属性需要加浏览器前缀  // 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";  }    // 添加一个标题改变的监听器  document.addEventListener(visibilityChange, function(e) {    // 开始或停止状态处理  }, false);  


3. getUserMedia API

该API允许Web应用程序访问摄像头和麦克风,而无需使用插件。

// 设置事件监听器  window.addEventListener("DOMContentLoaded", function() {    // 获取元素    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);       };      // 设置video监听器    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);  


4. 电池API(Battery API)

这是一个针对移动设备应用程序的API,主要用于检测设备电池信息。

var battery = navigator.battery || navigator.webkitBattery || navigator.mozBattery;    // 电池属性  console.warn("Battery charging: ", battery.charging); // true  console.warn("Battery level: ", battery.level); // 0.58  console.warn("Battery discharging time: ", battery.dischargingTime);    // 添加事件监听器  battery.addEventListener("chargingchange", function(e) {    console.warn("Battery charge change: ", battery.charging);  }, false);  


5. Link Prefetching

预加载网页内容,为浏览者提供一个平滑的浏览体验。

<!-- full page -->  <link rel="prefetch" href="http://davidwalsh.name/css-enhancements-user-experience" />    <!-- just an image -->  <link rel="prefetch" href="http://davidwalsh.name/wp-content/themes/walshbook3/images/sprite.png" />  


本文转载自:www.iteye.com/news/26489


实现页面录音功能参考:www.jb51.net/article/162…