你可能不知道的5个功能强大的 HTML5 API

// 根据目标元素调用相应的方法
function launchFullScreen(element) {
  if(element.requestFullScreen) {
    element.requestFullScreen();
  } else if(element.mozRequestFullScreen) {
    element.mozRequestFullScreen();
  } else if(element.webkitRequestFullScreen) {
    element.webkitRequestFullScreen();
  }
}

// 在支持的浏览器中启动全屏
launchFullScreen(document.documentElement); // 整个页面
launchFullScreen(document.getElementById("videoElement")); // 单个元素

// 部分浏览器只支持 vendor-prefixed
// 根据浏览器支持情况设置隐藏属性和可见状态改变事件
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";
}

// 添加一个时间来实时改变页面的标题
document.addEventListener(visibilityChange, function(e) {
  // Start or stop processing depending on state
}, false);

// 添加事件监听器
window.addEventListener("DOMContentLoaded", function() {
  // 获取元素，创建配置
  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); 
    };

  // 添加视频监听器
  if(navigator.getUserMedia) { // 标准的API
    navigator.getUserMedia(videoObj, function(stream) {
      video.src = stream;
      video.play();
    }, errBack);
  } else if(navigator.webkitGetUserMedia) { // WebKit 核心的API
    navigator.webkitGetUserMedia(videoObj, function(stream){
      video.src = window.webkitURL.createObjectURL(stream);
      video.play();
    }, errBack);
  }
}, false);

// 获取电池对象
var battery = navigator.battery || navigator.webkitBattery || navigator.mozBattery;

// 一组非常有用的电池属性
console.warn("Battery charging: ", battery.charging); // true
console.warn("Battery level: ", battery.level); // 0.58
console.warn("Battery discharging time: ", battery.dischargingTime);

// 监听电池状态
battery.addEventListener("chargingchange", function(e) {
  console.warn("Battery charge change: ", battery.charging);
}, false);

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