HTML5的这些api你知道吗？

// 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);

    // 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

// Whack fullscreenfunction exitFullscreen() {
  if(document.exitFullscreen) {
    document.exitFullscreen();
  } else if(document.mozCancelFullScreen) {
    document.mozCancelFullScreen();
  } else if(document.webkitExitFullscreen) {
    document.webkitExitFullscreen();
  }
}

// Cancel fullscreen for browsers that support it!
exitFullscreen();

:-webkit-full-screen,
:-moz-full-screen,
:-ms-fullscreen,
:full-screen {
    /*pre-spec */
   /* properties */
}
:fullscreen { 
    /* spec */
   /* properties */
}
/* deeper elements */:-webkit-full-screen video {
   width: 100%;
   height: 100%;
}
/* styling the backdrop*/::backdrop {
  /* properties */
}
::-ms-backdrop {
  /* properties */
}

<!--
    正常正确情况下，使用video等元素，我们是需要在确认客户端是支持该元素时才
    回相应地用js创建这些元素，但通过使用getUserMedia api，
    我们即可在html中直接创建这些元素（而不需要用js来创建）,
-->
    <video id="video" width="640" height="480" autoplay></video>
    <button id="snap">Snap Photo</button>
    <canvas id="canvas" width="640" height="480"></canvas>

// 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);

var battery = navigator.battery || navigator.webkitBattery || navigator.mozBattery;  

// 电池属性  
console.warn("Battery charging: ", battery.charging); // 当前电池是否在充电 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);

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