HTML5入门

阿才哥 · 发表于 2019-7-30 12:19:00

HTML5的初步认识

一、HTML5的初步认识

关于html5的一些历史可以通过这篇博客了解：https://www.cnblogs.com/fly_dragon/archive/2012/05/22/2513716.html

1.为HTML5建立的一些规则：

新特性应该基于HTML、CSS、DOM以及JavaScript
减少对外部插件的需求（比如flash）
更优秀的错误处理
更多取代脚本的标记
HTML5应该独立于设备
开发进程应对公众透明

2.HTML5新特性

用于绘画的canvas元素svg
用于媒介回放的video和audio元素
对本地离线存储的更好的支持：localStorage、sessionStorage
新的特殊内容元素，比如article、footer、header、nav、section
新的表单控件，比如calendar、date、time、email、url、search（）
input type = text button file radio checkbox（html）

新的的特殊内容元素：article、footer、header、nav、section本质上与div没什么区别，只是为了更加方便的阅读代码而产生的语义化标签：(article与section的区别一个相当于div一个相当于p)

<header>头部、首部标签</header>
<nav>导航</nav>
<article>文章（div）</article>
<section>章节(p)</section>
<footer>底部</footer>

在HTML5中还允许自定义标签，自定义的标签属于行级元素，类似span。

<student></student><span></span>

2.HTML5新属性

Contenteditable用户能否修改页面上的内容
Draggable支持拖放
Hidden隐藏
Contextmenu为元素设定快捷菜单（目前无浏览器支持contextmenu属性）
data-val自定义属性

2.1contenteditable的属性值为boolean类型，当值为true表示当前元素内容可以编辑，默认为false不能编辑：

<div contenteditable="true">这个div可以编辑：</div>

实现效果：

以下是基于contenteditable属性实现的富文本编辑器的代码：

  1 <!DOCTYPE html>
  2 <html>
  3 <head>
  4     <meta charset="utf-8">
  5     <meta http-equiv="X-UA-Compatible" content="IE=edge">
  6     <title>富文本编辑器【Rich Text Editor】</title>
  7     <link rel="stylesheet" href="">
  8     <script type="text/javascript">
  9         var oDoc,sDefTxt;
 10         function initDoc(){
 11             oDoc = document.getElementById("textBox");
 12             sDefTxt = oDoc.innerHTML;
 13             if(document.compForm.switchMode.checked){
 14                 setDocMode(true);
 15             }
 16         }
 17         function formatDoc(sCmd, sValue){
 18             if(validateMode()){
 19                 document.execCommand(sCmd, false, sValue);
 20                 oDoc.focus();
 21             }
 22         }
 23         function validateMode(){
 24             if(!document.compForm.switchMode.checked){
 25                 return true;
 26             }
 27             alert("Uncheck\"Show Html\".");
 28             oDoc.focus();
 29             return false;
 30         }
 31         function setDocMode(bToSource){
 32             var oContent;
 33             if(bToSource){
 34                 oContent = document.createTextNode(oDoc.innerHTML);
 35                 oDoc.innerHTML = "";
 36                 var oPre = document.createElement("pre");
 37                 oDoc.contentEditable = false;
 38                 oPre.id = "sourceText";
 39                 oPre.contentEditable = true;
 40                 oPre.appendChild(oContent);
 41                 oDoc.appendChild(oPre);
 42                 document.execCommand("defaultParagraphSeparator", false, "div");
 43             }else{
 44                 if(document.all){
 45                     oDoc.innerHTML = oDoc.innerText;
 46                 }else{
 47                     oContent = document.createRange();
 48                     oContent.selectNodeContents(oDoc.firstChild);
 49                     oDoc.innerHTML = oContent.toString();
 50                 }
 51                 oDoc.contentEditable = true;
 52             }
 53             oDoc.focus();
 54         }
 55         function printDoc(){
 56             if(!validateMode()){
 57                 return ;
 58             }
 59             var oPrntWin = windowl.open("","_blank","width=450,height=470,left=400,top=100,menubar=yes,toolbar=no,location=no,scrollbars=yes");
 60             oPrntWin.document.open();
 61             oPrntWin.document.write("<!doctype html><html><title>Print<\/title><\/head><body onload=\"print();\">" + oDoc.innerHTML + "<\/body><\/html>");
 62             oPrntWin.document.close();
 63         }
 64     </script>
 65     <style type="text/css">
 66         .intLink { 
 67             cursor: pointer; 
 68         }
 69         img.intLink { 
 70             border: 0; 
 71         }
 72         #toolBar1 select { 
 73             font-size:10px; 
 74         }
 75         #textBox {
 76           width: 540px;
 77           height: 200px;
 78           border: 1px #000000 solid;
 79           padding: 12px;
 80           overflow: scroll;
 81         }
 82         #textBox #sourceText {
 83           padding: 0;
 84           margin: 0;
 85           min-width: 498px;
 86           min-height: 200px;
 87         }
 88         #editMode label { 
 89             cursor: pointer;
 90         }
 91     </style>
 92 </head>
 93 <body onload="initDoc();">
 94     <form name="compForm" method="post" action="sample.php" onsubmit="if(validateMode()){this.myDoc.value=oDoc.innerHTML;return true;}return false;">
 95     <input type="hidden" name="myDoc">
 96     <div id="toolBar1">
 97         <select onchange="formatDoc('formatblock',this[this.selectedIndex].value);this.selectedIndex=0;">
 98             <option selected>- formatting -</option>
 99             <option value="h1">Title 1 &lt;h1&gt;</option>
100             <option value="h2">Title 2 &lt;h2&gt;</option>
101             <option value="h3">Title 3 &lt;h3&gt;</option>
102             <option value="h4">Title 4 &lt;h4&gt;</option>
103             <option value="h5">Title 5 &lt;h5&gt;</option>
104             <option value="h6">Subtitle &lt;h6&gt;</option>
105             <option value="p">Paragraph &lt;p&gt;</option>
106             <option value="pre">Preformatted &lt;pre&gt;</option>
107         </select>
108         <select onchange="formatDoc('fontname',this[this.selectedIndex].value);this.selectedIndex=0;">
109             <option class="heading" selected>- font -</option>
110             <option>Arial</option>
111             <option>Arial Black</option>
112             <option>Courier New</option>
113             <option>Times New Roman</option>
114         </select>
115         <select onchange="formatDoc('fontsize',this[this.selectedIndex].value);this.selectedIndex=0;">
116             <option class="heading" selected>- size -</option>
117             <option value="1">Very small</option>
118             <option value="2">A bit small</option>
119             <option value="3">Normal</option>
120             <option value="4">Medium-large</option>
121             <option value="5">Big</option>
122             <option value="6">Very big</option>
123             <option value="7">Maximum</option>
124         </select>
125         <select onchange="formatDoc('forecolor',this[this.selectedIndex].value);this.selectedIndex=0;">
126             <option class="heading" selected>- color -</option>
127             <option value="red">Red</option>
128             <option value="blue">Blue</option>
129             <option value="green">Green</option>
130             <option value="black">Black</option>
131         </select>
132         <select onchange="formatDoc('backcolor',this[this.selectedIndex].value);this.selectedIndex=0;">
133             <option class="heading" selected>- background -</option>
134             <option value="red">Red</option>
135             <option value="green">Green</option>
136             <option value="black">Black</option>
137         </select>
138         <div id="toolBar2">
139             <img class="intLink" title="Clean" onclick="if(validateMode()&&confirm('Are you sure?')){oDoc.innerHTML=sDefTxt};" src="data:image/gif;base64,R0lGODlhFgAWAIQbAD04KTRLYzFRjlldZl9vj1dusY14WYODhpWIbbSVFY6O7IOXw5qbms+wUbCztca0ccS4kdDQjdTLtMrL1O3YitHa7OPcsd/f4PfvrvDv8Pv5xv///////////////////yH5BAEKAB8ALAAAAAAWABYAAAV84CeOZGmeaKqubMteyzK547QoBcFWTm/jgsHq4rhMLoxFIehQQSAWR+Z4IAyaJ0kEgtFoLIzLwRE4oCQWrxoTOTAIhMCZ0tVgMBQKZHAYyFEWEV14eQ8IflhnEHmFDQkAiSkQCI2PDC4QBg+OAJc0ewadNCOgo6anqKkoIQA7" />
140             <img class="intLink" title="Print" onclick="printDoc();" src="data:image/png;base64,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">
141             <img class="intLink" title="Undo" onclick="formatDoc('undo');" src="data:image/gif;base64,R0lGODlhFgAWAOMKADljwliE33mOrpGjuYKl8aezxqPD+7/I19DV3NHa7P///////////////////////yH5BAEKAA8ALAAAAAAWABYAAARR8MlJq7046807TkaYeJJBnES4EeUJvIGapWYAC0CsocQ7SDlWJkAkCA6ToMYWIARGQF3mRQVIEjkkSVLIbSfEwhdRIH4fh/DZMICe3/C4nBQBADs=" />
142             <img class="intLink" title="Redo" onclick="formatDoc('redo');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAB1ChDljwl9vj1iE34Kl8aPD+7/I1////yH5BAEKAAcALAAAAAAWABYAAANKeLrc/jDKSesyphi7SiEgsVXZEATDICqBVJjpqWZt9NaEDNbQK1wCQsxlYnxMAImhyDoFAElJasRRvAZVRqqQXUy7Cgx4TC6bswkAOw==" />
143             <img class="intLink" title="Remove formatting" onclick="formatDoc('removeFormat')" src="data:image/png;base64,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">
144             <img class="intLink" title="Bold" onclick="formatDoc('bold');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAInhI+pa+H9mJy0LhdgtrxzDG5WGFVk6aXqyk6Y9kXvKKNuLbb6zgMFADs=" />
145             <img class="intLink" title="Italic" onclick="formatDoc('italic');" src="data:image/gif;base64,R0lGODlhFgAWAKEDAAAAAF9vj5WIbf///yH5BAEAAAMALAAAAAAWABYAAAIjnI+py+0Po5x0gXvruEKHrF2BB1YiCWgbMFIYpsbyTNd2UwAAOw==" />
146             <img class="intLink" title="Underline" onclick="formatDoc('underline');" src="data:image/gif;base64,R0lGODlhFgAWAKECAAAAAF9vj////////yH5BAEAAAIALAAAAAAWABYAAAIrlI+py+0Po5zUgAsEzvEeL4Ea15EiJJ5PSqJmuwKBEKgxVuXWtun+DwxCCgA7" />
147             <img class="intLink" title="Left align" onclick="formatDoc('justifyleft');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JMGELkGYxo+qzl4nKyXAAAOw==" />
148             <img class="intLink" title="Center align" onclick="formatDoc('justifycenter');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIfhI+py+0Po5y02ouz3jL4D4JOGI7kaZ5Bqn4sycVbAQA7" />
149             <img class="intLink" title="Right align" onclick="formatDoc('justifyright');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JQGDLkGYxouqzl43JyVgAAOw==" />
150             <img class="intLink" title="Numbered list" onclick="formatDoc('insertorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAADljwliE35GjuaezxtHa7P///////yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKSespwjoRFvggCBUBoTFBeq6QIAysQnRHaEOzyaZ07Lu9lUBnC0UGQU1K52s6n5oEADs=" />
151             <img class="intLink" title="Dotted list" onclick="formatDoc('insertunorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAAB1ChF9vj1iE33mOrqezxv///////yH5BAEAAAcALAAAAAAWABYAAAMyeLrc/jDKSesppNhGRlBAKIZRERBbqm6YtnbfMY7lud64UwiuKnigGQliQuWOyKQykgAAOw==" />
152             <img class="intLink" title="Quote" onclick="formatDoc('formatblock','blockquote');" src="data:image/gif;base64,R0lGODlhFgAWAIQXAC1NqjFRjkBgmT9nqUJnsk9xrFJ7u2R9qmKBt1iGzHmOrm6Sz4OXw3Odz4Cl2ZSnw6KxyqO306K63bG70bTB0rDI3bvI4P///////////////////////////////////yH5BAEKAB8ALAAAAAAWABYAAAVP4CeOZGmeaKqubEs2CekkErvEI1zZuOgYFlakECEZFi0GgTGKEBATFmJAVXweVOoKEQgABB9IQDCmrLpjETrQQlhHjINrTq/b7/i8fp8PAQA7" />
153             <img class="intLink" title="Delete indentation" onclick="formatDoc('outdent');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAAAAADljwliE35GjuaezxtDV3NHa7P///yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKCQG9F2i7u8agQgyK1z2EIBil+TWqEMxhMczsYVJ3e4ahk+sFnAgtxSQDqWw6n5cEADs=" />
154             <img class="intLink" title="Add indentation" onclick="formatDoc('indent');" src="data:image/gif;base64,R0lGODlhFgAWAOMIAAAAADljwl9vj1iE35GjuaezxtDV3NHa7P///////////////////////////////yH5BAEAAAgALAAAAAAWABYAAAQ7EMlJq704650B/x8gemMpgugwHJNZXodKsO5oqUOgo5KhBwWESyMQsCRDHu9VOyk5TM9zSpFSr9gsJwIAOw==" />
155             <img class="intLink" title="Hyperlink" onclick="var sLnk=prompt('Write the URL here','http:\/\/');if(sLnk&&sLnk!=''&&sLnk!='http://'){formatDoc('createlink',sLnk)}" src="data:image/gif;base64,R0lGODlhFgAWAOMKAB1ChDRLY19vj3mOrpGjuaezxrCztb/I19Ha7Pv8/f///////////////////////yH5BAEKAA8ALAAAAAAWABYAAARY8MlJq7046827/2BYIQVhHg9pEgVGIklyDEUBy/RlE4FQF4dCj2AQXAiJQDCWQCAEBwIioEMQBgSAFhDAGghGi9XgHAhMNoSZgJkJei33UESv2+/4vD4TAQA7" />
156             <img class="intLink" title="Cut" onclick="formatDoc('cut');" src="data:image/gif;base64,R0lGODlhFgAWAIQSAB1ChBFNsRJTySJYwjljwkxwl19vj1dusYODhl6MnHmOrpqbmpGjuaezxrCztcDCxL/I18rL1P///////////////////////////////////////////////////////yH5BAEAAB8ALAAAAAAWABYAAAVu4CeOZGmeaKqubDs6TNnEbGNApNG0kbGMi5trwcA9GArXh+FAfBAw5UexUDAQESkRsfhJPwaH4YsEGAAJGisRGAQY7UCC9ZAXBB+74LGCRxIEHwAHdWooDgGJcwpxDisQBQRjIgkDCVlfmZqbmiEAOw==" />
157             <img class="intLink" title="Copy" onclick="formatDoc('copy');" src="data:image/gif;base64,R0lGODlhFgAWAIQcAB1ChBFNsTRLYyJYwjljwl9vj1iE31iGzF6MnHWX9HOdz5GjuYCl2YKl8ZOt4qezxqK63aK/9KPD+7DI3b/I17LM/MrL1MLY9NHa7OPs++bx/Pv8/f///////////////yH5BAEAAB8ALAAAAAAWABYAAAWG4CeOZGmeaKqubOum1SQ/kPVOW749BeVSus2CgrCxHptLBbOQxCSNCCaF1GUqwQbBd0JGJAyGJJiobE+LnCaDcXAaEoxhQACgNw0FQx9kP+wmaRgYFBQNeAoGihCAJQsCkJAKOhgXEw8BLQYciooHf5o7EA+kC40qBKkAAAGrpy+wsbKzIiEAOw==" />
158             <img class="intLink" title="Paste" onclick="formatDoc('paste');" src="data:image/gif;base64,R0lGODlhFgAWAIQUAD04KTRLY2tXQF9vj414WZWIbXmOrpqbmpGjudClFaezxsa0cb/I1+3YitHa7PrkIPHvbuPs+/fvrvv8/f///////////////////////////////////////////////yH5BAEAAB8ALAAAAAAWABYAAAWN4CeOZGmeaKqubGsusPvBSyFJjVDs6nJLB0khR4AkBCmfsCGBQAoCwjF5gwquVykSFbwZE+AwIBV0GhFog2EwIDchjwRiQo9E2Fx4XD5R+B0DDAEnBXBhBhN2DgwDAQFjJYVhCQYRfgoIDGiQJAWTCQMRiwwMfgicnVcAAAMOaK+bLAOrtLUyt7i5uiUhADs=" />
159         </div>
160         <div id="textBox" contenteditable="true"><p>Lorem ipsum</p></div>
161         <p id="editMode"><input type="checkbox" name="switchMode" id="switchBox" onchange="setDocMode(this.checked);" /> <label for="switchBox">Show HTML</label></p>
162         <p><input type="submit" value="Send" /></p>
163     </form>
164 </body>
165 </html>

富文本编辑器代码

2.2关于Draggable属性实现元素拖拽：

　　2.2.1属性：draggable: auto | true | false

　　2.2.2拖拽事件：

dragstart 在元素开始被拖动时触发
dragend 在拖动操作完成时触发
drag 在元素被拖动时触发

　　2.2.3释放区域事件：

dragenter 被拖动元素进入到释放区所占据得屏幕空间时触发
dragover 当被拖动元素在释放区内移动时触发
dragleave 当被拖动元素没有放下就离开释放区时触发
drop 当被拖动元素在释放区里放下时触发

 1 <!DOCTYPE HTML>
 2 <html>
 3 <head>
 4 <meta charset="utf-8">
 5 <title>菜鸟教程(runoob.com)</title>
 6 <style>
 7 .droptarget {
 8     float: left; 
 9     width: 100px; 
10     height: 35px;
11     margin: 15px;
12     padding: 10px;
13     border: 1px solid #aaaaaa;
14 }
15 </style>
16 </head>
17 <body>
18 
19 <p>在两个矩形框中来回拖动 p 元素:</p>
20 <div class="droptarget">
21     <p draggable="true" id="dragtarget">拖动我!</p>
22 </div>
23 <div class="droptarget"></div>
24 <p style="clear:both;"><strong>注意：</strong>Internet Explorer 8 及更早 IE 版本或 Safari 5.1 及更早版本的浏览器不支持 drag 事件。</p>
25 <p id="demo"></p>
26 <script>
27 /* 拖动时触发*/
28 document.addEventListener("dragstart", function(event) {
29     //dataTransfer.setData()方法设置数据类型和拖动的数据
30     console.log(event.dataTransfer);
31     event.dataTransfer.setData("Text", event.target.id);
32     // 拖动 p 元素时输出一些文本
33     document.getElementById("demo").innerHTML = "开始拖动 p 元素.";    
34     //修改拖动元素的透明度
35     event.target.style.opacity = "0.4";
36 });
37 //在拖动p元素的同时,改变输出文本的颜色
38 document.addEventListener("drag", function(event) {
39     document.getElementById("demo").style.color = "red";
40 });
41 // 当拖完p元素输出一些文本元素和重置透明度
42 document.addEventListener("dragend", function(event) {
43     document.getElementById("demo").innerHTML = "完成 p 元素的拖动";
44     event.target.style.opacity = "1";
45 });
46 /* 拖动完成后触发 */
47 // 当p元素完成拖动进入droptarget,改变div的边框样式
48 document.addEventListener("dragenter", function(event) {
49     if ( event.target.className == "droptarget" ) {
50         event.target.style.border = "3px dotted red";
51     }
52 });
53 // 默认情况下,数据/元素不能在其他元素中被拖放。对于drop我们必须防止元素的默认处理
54 document.addEventListener("dragover", function(event) {
55     event.preventDefault();
56 });
57 // 当可拖放的p元素离开droptarget，重置div的边框样式
58 document.addEventListener("dragleave", function(event) {
59     if ( event.target.className == "droptarget" ) {
60         event.target.style.border = "";
61     }
62 });
63 /*对于drop,防止浏览器的默认处理数据(在drop中链接是默认打开)
64 复位输出文本的颜色和DIV的边框颜色
65 利用dataTransfer.getData()方法获得拖放数据
66 拖拖的数据元素id(“drag1”)
67 拖拽元素附加到drop元素*/
68 document.addEventListener("drop", function(event) {
69     event.preventDefault();
70     if ( event.target.className == "droptarget" ) {
71         document.getElementById("demo").style.color = "";
72         event.target.style.border = "";
73         var data = event.dataTransfer.getData("Text");
74         event.target.appendChild(document.getElementById(data));
75     }
76 });
77 </script>
78 
79 </body>
80 </html>

来自一个手册得完整示例

　　》》示例链接：https://www.runoob.com/try/try.php?filename=tryjsref_ondrag_all

2.3Hidden实现的元素隐藏本质上就是基于display的样式属性none实现的，这个隐藏的元素依然存在于文档结构中，只是display属性被设置为none了而已。

2.4自定义属性：

<div data-val="demo"></div>
document.getElementsByTagName('div')[0].getAttribute('data-val');//demo

HTML5入门

一、HTML5的初步认识

1.为HTML5建立的一些规则：

2.HTML5新特性

2.HTML5新属性

2.2.1属性：draggable: auto | true | false

2.2.2拖拽事件：

2.2.3释放区域事件：

浏览过的版块

　　2.2.1属性：draggable: auto | true | false

　　2.2.2拖拽事件：

　　2.2.3释放区域事件：