HTML5学习笔记
1.视频
<video src="test.mp4" controls="controls">
controls属性用来控制控件的显示
<!DOCTYPE html> <html> <body> <div style="text-align:center;"> <button onclick="playPause()">播放/暂停</button> <button onclick="makeBig()">大</button> <button onclick="makeNormal()">中</button> <button onclick="makeSmall()">小</button> <br /> <video id="video1" width="420" style="margin-top:15px;"> <source src="/example/html5/mov_bbb.mp4" type="video/mp4" /> <source src="/example/html5/mov_bbb.ogg" type="video/ogg" /> Your browser does not support HTML5 video. </video> </div> <script type="text/javascript"> var myVideo=document.getElementById("video1"); function playPause() { if (myVideo.paused) myVideo.play(); else myVideo.pause(); } function makeBig() { myVideo.width=560; } function makeSmall() { myVideo.width=320; } function makeNormal() { myVideo.width=420; } </script> </body> </html>
控制视频显示大小，暂停/播放视频。
2.音频
<audio src="song.mp3" controls="controls">
controls方法同上。
3.拖放
<!DOCTYPE HTML> <html> <head> <style type="text/css"> #div1 {width:488px;height:70px;padding:10px;border:1px solid #aaaaaa;} </style> <script type="text/javascript"> function allowDrop(ev) { ev.preventDefault(); } function drag(ev) { ev.dataTransfer.setData("Text",ev.target.id); } function drop(ev) { ev.preventDefault(); var data=ev.dataTransfer.getData("Text"); ev.target.appendChild(document.getElementById(data)); } </script> </head> <body> <p>请把 W3School 的图片拖放到矩形中：</p> <div id="div1" ondrop="drop(event)" ondragover="allowDrop(event)"></div> <br /> <img id="drag1" src="/i/w3school_banner.gif" draggable="true" ondragstart="drag(event)" /> </body> </html>
4.web存储
web存储主要借助JavaScript。以下的例子是用来统计用户访问网站的次数。
<script type="text/javascript"> if (localStorage.pagecount) { localStorage.pagecount=Number(localStorage.pagecount) +1; } else { localStorage.pagecount=1; } document.write("Visits "+ localStorage.pagecount + " time(s)."); </script>
当用sessionStorage代替localStorage时，只要用户关闭浏览器，数据清零。
5.应用程序缓存
<!DOCTYPE HTML> <html manifest="demo.appcache"> ... </html>
如此操作时，可供离线浏览。下次加载时，只加载更新的部分，节省服务器开销，速度更快。
6.web worker
<!DOCTYPE html> <html> <body> <p>计数: <output id="result"></output></p> <button onclick="startWorker()">开始 Worker</button> <button onclick="stopWorker()">停止 Worker</button> <br /><br /> <script> var w; function startWorker() { if(typeof(Worker)!=="undefined") { if(typeof(w)=="undefined") { w=new Worker("/example/html5/demo_workers.js"); } w.onmessage = function (event) { document.getElementById("result").innerHTML=event.data; }; } else { document.getElementById("result").innerHTML="Sorry, your browser does not support Web Workers..."; } } function stopWorker() { w.terminate(); } </script> </body> </html>
web worker在后台运行，不会影响到其他脚本。web worker多用于耗费CPU多的项目。
7.服务器发送事件
<script> if(typeof(EventSource)!=="undefined") { var source=new EventSource("/example/html5/demo_sse.php"); source.onmessage=function(event) { document.getElementById("result").innerHTML+=event.data + "<br />"; }; } else { document.getElementById("result").innerHTML="Sorry, your browser does not support server-sent events..."; } </script>
对应的PHP
<?php header('Content-Type: text/event-stream'); header('Cache-Control: no-cache'); $time = date('r'); echo "data: The server time is: {$time}\n\n"; flush(); ?>
8.input 类型
<input type="email" name="user_email" />
email可以换成number，url等。
9.datalist是规定输入域的选项列表
<!DOCTYPE HTML> <html> <body> <form action="/example/html5/demo_form.asp" method="get"> Webpage: <input type="url" list="url_list" name="link" /> <datalist id="url_list"> <option label="W3School" value="http://www.w3school.com.cn" /> <option label="Google" value="http://www.google.com" /> <option label="Microsoft" value="http://www.microsoft.com" /> </datalist> <input type="submit" /> </form> </body> </html>