你可能不知道的5個(gè)強(qiáng)大的HTML5 API
1. 全屏API(Fullscreen API)
該API允許開(kāi)發(fā)者以編程方式將Web應(yīng)用程序全屏運(yùn)行,使Web應(yīng)用程序更像本地應(yīng)用程序。
- // 找到適合瀏覽器的全屏方法
- function launchFullScreen(element) {
- if(element.requestFullScreen) {
- element.requestFullScreen();
- } else if(element.mozRequestFullScreen) {
- element.mozRequestFullScreen();
- } else if(element.webkitRequestFullScreen) {
- element.webkitRequestFullScreen();
- }
- }
- // 啟動(dòng)全屏模式
- launchFullScreen(document.documentElement); // the whole page
- launchFullScreen(document.getElementById("videoElement")); // any individual element
2. 頁(yè)面可見(jiàn)性API(Page Visibility API)
該API可以用來(lái)檢測(cè)頁(yè)面對(duì)于用戶(hù)的可見(jiàn)性,即返回用戶(hù)當(dāng)前瀏覽的頁(yè)面或標(biāo)簽的狀態(tài)變化。
- // 設(shè)置隱藏屬性和可見(jiàn)改變事件的名稱(chēng),屬性需要加瀏覽器前綴
- // 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";
- }
- // 添加一個(gè)標(biāo)題改變的監(jiān)聽(tīng)器
- document.addEventListener(visibilityChange, function(e) {
- // 開(kāi)始或停止?fàn)顟B(tài)處理
- }, false);
3. getUserMedia API
該API允許Web應(yīng)用程序訪問(wèn)攝像頭和麥克風(fēng),而無(wú)需使用插件。
- // 設(shè)置事件監(jiān)聽(tīng)器
- window.addEventListener("DOMContentLoaded", function() {
- // 獲取元素
- 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);
- };
- // 設(shè)置video監(jiān)聽(tīng)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. 電池API(Battery API)
這是一個(gè)針對(duì)移動(dòng)設(shè)備應(yīng)用程序的API,主要用于檢測(cè)設(shè)備電池信息。
- var battery = navigator.battery || navigator.webkitBattery || navigator.mozBattery;
- // 電池屬性
- console.warn("Battery charging: ", battery.charging); // true
- console.warn("Battery level: ", battery.level); // 0.58
- console.warn("Battery discharging time: ", battery.dischargingTime);
- // 添加事件監(jiān)聽(tīng)器
- battery.addEventListener("chargingchange", function(e) {
- console.warn("Battery charge change: ", battery.charging);
- }, false);
5. Link Prefetching
預(yù)加載網(wǎng)頁(yè)內(nèi)容,為瀏覽者提供一個(gè)平滑的瀏覽體驗(yàn)。
- <!-- 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" />