contentEditable,window.getSelection详解---可编辑div，容器，设置/获取光标位置，光标处插入内容及光标的操作

这周碰到一个东西，contentEditable ，它是用来指定一个元素是否是可编辑的，这也是富文本编辑器实现的底层支持，网上关于这部分东西的资料比较少或者不全，所以我来整理下关于这个属性，和可编辑区域的一些操作吧，比如获取光标位置，设置光标，往可编辑区域光标处插入内容等等

HTML中的contentEditable的属性可以打开某些元素的可编辑状态．也许你没用过contentEditable属性．甚至从未听说过．contentEditable的作用相当神奇．可以让div或整个网页，以及span等等元素设置为可写。我们最常用的输入文本内容便是input与textarea，使用contentEditable属性后，可以在div,table,p,span,body,等等很多元素中输入内容．

设置一个容器为可编辑区域:设置contentEditable属性

<body>
	<p contentEditable style="border: 1px solid red;">grsd</p>
	<div  contentEditable style="border: 1px solid red;">rsdgsdg </div>
</body>

在这里插入图片描述

设置placeholder：
这个不像表单一样，给属性加上placeholder属性指定值就可以了，还需要配合特殊的样式:empty做设置

	<style type="text/css">
			.content:empty::before {
     
     
				content: attr(placeholder);
				font-size: 14px;
				color: #CCC;
				line-height: 21px;
				padding-top: 20px;
			}
			.content {
     
     
				border: 1px solid black;
			}
		</style>
	<body>
		<div contentEditable class="content" placeholder="请输入不少于150字"></div>
	</body>

在这里插入图片描述

回车时，在标记生成上的不同点

因为各个浏览器在标记生成上的不同，因此跨浏览器使用 contenteditable 一直以来都是痛点，例如一些看起来十分简单的事情，如：当你按下Enter/Return键在可编辑区域中创建一个新的文本行时，不同主流浏览器对此有不同处理(Firefox 插入<br>、IE/Opera将使用<p>、 Chrome/Safari 将使用 <div>）幸运的是在现代浏览器中，这些不同都趋于一致了。截止到Firefox 60，火狐开始使用<div>元素来包裹新生成的文本行，以与Chrome, modern Opera, Edge, and Safari.的行为趋于一致

改变回车时插入的标签：
如果你想使用不同的方式创建新的段落,上面所有浏览器都支持document.execCommand方法，该方法提供的 defaultParagraphSeparator 命令能够让你以不同的方式创建新的段落例如, 使用 <p> 元素:

document.execCommand("defaultParagraphSeparator", false, "p");

现在在编辑器中按回车就变成p标签了
在这里插入图片描述

document.execCommand的强大：

上面只是document.execCommand的一个命令演示

当一个HTML文档切换到设计模式时，document暴露 execCommand 方法，该方法允许运行命令来操纵可编辑内容区域的元素。
大多数命令影响document的 selection（粗体，斜体等），当其他命令插入新元素（添加链接）或影响整行（缩进）。当使用contentEditable时，调用 execCommand() 将影响当前活动的可编辑元素。

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命令很多，这里就不列举出来，具体可以参考官方文档document.execCommand命令大全

基于document.execCommand的这些命令，我们可以做一个小型的富文本编辑器：

<!doctype html>
<html>
	<head>
		<title>Rich Text Editor</title>
		<script type="text/javascript">
			var oDoc, sDefTxt;

			function initDoc() {
     
     
				oDoc = document.getElementById("textBox");
				sDefTxt = oDoc.innerHTML;
				if(document.compForm.switchMode.checked) {
     
     
					setDocMode(true);
				}
			}

			function formatDoc(sCmd, sValue) {
     
     
				if(validateMode()) {
     
     
					document.execCommand(sCmd, false, sValue);
					oDoc.focus();
				}
			}

			function validateMode() {
     
     
				if(!document.compForm.switchMode.checked) {
     
     
					return true;
				}
				alert("Uncheck \"Show HTML\".");
				oDoc.focus();
				return false;
			}

			function setDocMode(bToSource) {
     
     
				var oContent;
				if(bToSource) {
     
     
					oContent = document.createTextNode(oDoc.innerHTML);
					oDoc.innerHTML = "";
					var oPre = document.createElement("pre");
					oDoc.contentEditable = false;
					oPre.id = "sourceText";
					oPre.contentEditable = true;
					oPre.appendChild(oContent);
					oDoc.appendChild(oPre);
					document.execCommand("defaultParagraphSeparator", false, "div");
				} else {
     
     
					if(document.all) {
     
     
						oDoc.innerHTML = oDoc.innerText;
					} else {
     
     
						oContent = document.createRange();
						oContent.selectNodeContents(oDoc.firstChild);
						oDoc.innerHTML = oContent.toString();
					}
					oDoc.contentEditable = true;
				}
				oDoc.focus();
			}

			function printDoc() {
     
     
				if(!validateMode()) {
     
     
					return;
				}
				var oPrntWin = window.open("", "_blank", "width=450,height=470,left=400,top=100,menubar=yes,toolbar=no,location=no,scrollbars=yes");
				oPrntWin.document.open();
				oPrntWin.document.write("<!doctype html><html><head><title>Print<\/title><\/head><body οnlοad=\"print();\">" + oDoc.innerHTML + "<\/body><\/html>");
				oPrntWin.document.close();
			}
		</script>
		<style type="text/css">
			.intLink {
     
     
				cursor: pointer;
			}
			
			img.intLink {
     
     
				border: 0;
			}
			
			#toolBar1 select {
     
     
				font-size: 10px;
			}
			
			#textBox {
     
     
				width: 540px;
				height: 200px;
				border: 1px #000000 solid;
				padding: 12px;
				overflow: scroll;
			}
			
			#textBox #sourceText {
     
     
				padding: 0;
				margin: 0;
				min-width: 498px;
				min-height: 200px;
			}
			
			#editMode label {
     
     
				cursor: pointer;
			}
		</style>
	</head>

	<body onload="initDoc();">
		<form name="compForm" method="post" action="sample.php" onsubmit="if(validateMode()){this.myDoc.value=oDoc.innerHTML;return true;}return false;">
			<input type="hidden" name="myDoc">
			<div id="toolBar1">
				<select onchange="formatDoc('formatblock',this[this.selectedIndex].value);this.selectedIndex=0;">
					<option selected>- formatting -</option>
					<option value="h1">Title 1 &lt;h1&gt;</option>
					<option value="h2">Title 2 &lt;h2&gt;</option>
					<option value="h3">Title 3 &lt;h3&gt;</option>
					<option value="h4">Title 4 &lt;h4&gt;</option>
					<option value="h5">Title 5 &lt;h5&gt;</option>
					<option value="h6">Subtitle &lt;h6&gt;</option>
					<option value="p">Paragraph &lt;p&gt;</option>
					<option value="pre">Preformatted &lt;pre&gt;</option>
				</select>
				<select onchange="formatDoc('fontname',this[this.selectedIndex].value);this.selectedIndex=0;">
					<option class="heading" selected>- font -</option>
					<option>Arial</option>
					<option>Arial Black</option>
					<option>Courier New</option>
					<option>Times New Roman</option>
				</select>
				<select onchange="formatDoc('fontsize',this[this.selectedIndex].value);this.selectedIndex=0;">
					<option class="heading" selected>- size -</option>
					<option value="1">Very small</option>
					<option value="2">A bit small</option>
					<option value="3">Normal</option>
					<option value="4">Medium-large</option>
					<option value="5">Big</option>
					<option value="6">Very big</option>
					<option value="7">Maximum</option>
				</select>
				<select onchange="formatDoc('forecolor',this[this.selectedIndex].value);this.selectedIndex=0;">
					<option class="heading" selected>- color -</option>
					<option value="red">Red</option>
					<option value="blue">Blue</option>
					<option value="green">Green</option>
					<option value="black">Black</option>
				</select>
				<select onchange="formatDoc('backcolor',this[this.selectedIndex].value);this.selectedIndex=0;">
					<option class="heading" selected>- background -</option>
					<option value="red">Red</option>
					<option value="green">Green</option>
					<option value="black">Black</option>
				</select>
			</div>
			<div id="toolBar2">
				<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" />
				<img class="intLink" title="Print" onclick="printDoc();" src="data:image/png;base64,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">
				<img class="intLink" title="Undo" onclick="formatDoc('undo');" src="data:image/gif;base64,R0lGODlhFgAWAOMKADljwliE33mOrpGjuYKl8aezxqPD+7/I19DV3NHa7P///yH5BAEKAA8ALAAAAAAWABYAAARR8MlJq7046807TkaYeJJBnES4EeUJvIGapWYAC0CsocQ7SDlWJkAkCA6ToMYWIARGQF3mRQVIEjkkSVLIbSfEwhdRIH4fh/DZMICe3/C4nBQBADs=" />
				<img class="intLink" title="Redo" onclick="formatDoc('redo');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAB1ChDljwl9vj1iE34Kl8aPD+7/I1yH5BAEKAAcALAAAAAAWABYAAANKeLrc/jDKSesyphi7SiEgsVXZEATDICqBVJjpqWZt9NaEDNbQK1wCQsxlYnxMAImhyDoFAElJasRRvAZVRqqQXUy7Cgx4TC6bswkAOw==" />
				<img class="intLink" title="Remove formatting" onclick="formatDoc('removeFormat')" src="data:image/png;base64,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">
				<img class="intLink" title="Bold" onclick="formatDoc('bold');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAInhI+pa+H9mJy0LhdgtrxzDG5WGFVk6aXqyk6Y9kXvKKNuLbb6zgMFADs=" />
				<img class="intLink" title="Italic" onclick="formatDoc('italic');" src="data:image/gif;base64,R0lGODlhFgAWAKEDAAAAAF9vj5WIbf///yH5BAEAAAMALAAAAAAWABYAAAIjnI+py+0Po5x0gXvruEKHrF2BB1YiCWgbMFIYpsbyTNd2UwAAOw==" />
				<img class="intLink" title="Underline" onclick="formatDoc('underline');" src="data:image/gif;base64,R0lGODlhFgAWAKECAAAAAF9vjyH5BAEAAAIALAAAAAAWABYAAAIrlI+py+0Po5zUgAsEzvEeL4Ea15EiJJ5PSqJmuwKBEKgxVuXWtun+DwxCCgA7" />
				<img class="intLink" title="Left align" onclick="formatDoc('justifyleft');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JMGELkGYxo+qzl4nKyXAAAOw==" />
				<img class="intLink" title="Center align" onclick="formatDoc('justifycenter');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIfhI+py+0Po5y02ouz3jL4D4JOGI7kaZ5Bqn4sycVbAQA7" />
				<img class="intLink" title="Right align" onclick="formatDoc('justifyright');" src="data:image/gif;base64,R0lGODlhFgAWAID/AMDAwAAAACH5BAEAAAAALAAAAAAWABYAQAIghI+py+0Po5y02ouz3jL4D4JQGDLkGYxouqzl43JyVgAAOw==" />
				<img class="intLink" title="Numbered list" onclick="formatDoc('insertorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAADljwliE35GjuaezxtHa7P///yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKSespwjoRFvggCBUBoTFBeq6QIAysQnRHaEOzyaZ07Lu9lUBnC0UGQU1K52s6n5oEADs=" />
				<img class="intLink" title="Dotted list" onclick="formatDoc('insertunorderedlist');" src="data:image/gif;base64,R0lGODlhFgAWAMIGAAAAAB1ChF9vj1iE33mOrqezxv///yH5BAEAAAcALAAAAAAWABYAAAMyeLrc/jDKSesppNhGRlBAKIZRERBbqm6YtnbfMY7lud64UwiuKnigGQliQuWOyKQykgAAOw==" />
				<img class="intLink" title="Quote" onclick="formatDoc('formatblock','blockquote');" src="data:image/gif;base64,R0lGODlhFgAWAIQXAC1NqjFRjkBgmT9nqUJnsk9xrFJ7u2R9qmKBt1iGzHmOrm6Sz4OXw3Odz4Cl2ZSnw6KxyqO306K63bG70bTB0rDI3bvI4P///yH5BAEKAB8ALAAAAAAWABYAAAVP4CeOZGmeaKqubEs2CekkErvEI1zZuOgYFlakECEZFi0GgTGKEBATFmJAVXweVOoKEQgABB9IQDCmrLpjETrQQlhHjINrTq/b7/i8fp8PAQA7" />
				<img class="intLink" title="Delete indentation" onclick="formatDoc('outdent');" src="data:image/gif;base64,R0lGODlhFgAWAMIHAAAAADljwliE35GjuaezxtDV3NHa7P///yH5BAEAAAcALAAAAAAWABYAAAM2eLrc/jDKCQG9F2i7u8agQgyK1z2EIBil+TWqEMxhMczsYVJ3e4ahk+sFnAgtxSQDqWw6n5cEADs=" />
				<img class="intLink" title="Add indentation" onclick="formatDoc('indent');" src="data:image/gif;base64,R0lGODlhFgAWAOMIAAAAADljwl9vj1iE35GjuaezxtDV3NHa7P///yH5BAEAAAgALAAAAAAWABYAAAQ7EMlJq704650B/x8gemMpgugwHJNZXodKsO5oqUOgo5KhBwWESyMQsCRDHu9VOyk5TM9zSpFSr9gsJwIAOw==" />
				<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" />
				<img class="intLink" title="Cut" onclick="formatDoc('cut');" src="data:image/gif;base64,R0lGODlhFgAWAIQSAB1ChBFNsRJTySJYwjljwkxwl19vj1dusYODhl6MnHmOrpqbmpGjuaezxrCztcDCxL/I18rL1P///yH5BAEAAB8ALAAAAAAWABYAAAVu4CeOZGmeaKqubDs6TNnEbGNApNG0kbGMi5trwcA9GArXh+FAfBAw5UexUDAQESkRsfhJPwaH4YsEGAAJGisRGAQY7UCC9ZAXBB+74LGCRxIEHwAHdWooDgGJcwpxDisQBQRjIgkDCVlfmZqbmiEAOw==" />
				<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==" />
				<img class="intLink" title="Paste" onclick="formatDoc('paste');" src="data:image/gif;base64,R0lGODlhFgAWAIQUAD04KTRLY2tXQF9vj414WZWIbXmOrpqbmpGjudClFaezxsa0cb/I1+3YitHa7PrkIPHvbuPs+/fvrvv8/f///yH5BAEAAB8ALAAAAAAWABYAAAWN4CeOZGmeaKqubGsusPvBSyFJjVDs6nJLB0khR4AkBCmfsCGBQAoCwjF5gwquVykSFbwZE+AwIBV0GhFog2EwIDchjwRiQo9E2Fx4XD5R+B0DDAEnBXBhBhN2DgwDAQFjJYVhCQYRfgoIDGiQJAWTCQMRiwwMfgicnVcAAAMOaK+bLAOrtLUyt7i5uiUhADs=" />
			</div>
			<div id="textBox" contenteditable="true">
				<p>Lorem ipsum</p>
			</div>
			<p id="editMode"><input type="checkbox" name="switchMode" id="switchBox" onchange="setDocMode(this.checked);" /> <label for="switchBox">Show HTML</label></p>
			<p><input type="submit" value="Send" /></p>
		</form>
	</body>
</html>

在这里插入图片描述
是不是很酷？

window.getSelection()：文档地址

Selection 对象表示用户选择的文本范围或插入符号的当前位置。它代表页面中的文本选区，可能横跨多个元素。文本选区由用户拖拽鼠标经过文字而产生。要获取用于检查或修改的 Selection 对象，请调用 window.getSelection()。

Selection 对象所对应的是用户所选择的 ranges （区域），俗称拖蓝。默认情况下，该函数只针对一个区域，我们可以这样使用这个函数：

var selObj = window.getSelection();
var range  = selObj.getRangeAt(0);

例子： 我写了如下代码来一起探究下这两个是什么东西吧
每次我拖动完，或者点击完鼠标的时候，都会打印selObj，查看selObj对象，看看里面有什么属性

<body>
	<div>我是p标签的内容</div>
	<p>我是p标签的内容</p>
	<ul>
		<li>li1</li>
		<li>li2</li>
	</ul>
</body>
<script type="text/javascript">
	
	document.onmouseup=function(){
     
     
		var selObj = window.getSelection();
		console.log(selObj)
		var range  = selObj.getRangeAt(0);
		console.log(range)
	}
</script>

在这里插入图片描述
可以看到window.getSelection()打印的对象就是我们选中区域的对象，对象里面的属性值，我来介绍以下吧

而range对象里面的信息就简洁很多，这个我就不介绍了，和selection对象是一样的

当然range对象和selection对象原型上也有很多的方法提供给我们使用，可以自行查阅文档
selection对象的方法
 range对象的方法

我们要说的是基于这些方法，我们如何做到在可编辑的div或容器中往光标处插入内容，返回光标位置

通过js的方式在可编辑区域的光标处插入文本：

方法一：较完整的，考虑兼容，插入后，光标自动设置到插入后的位置

<!DOCTYPE html>
<html lang="zh">
<head>
	<meta charset="UTF-8" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<meta http-equiv="X-UA-Compatible" content="ie=edge" />
	<title>Document</title>
</head>
<body>
	<div class="box" contenteditable  style="border: 1px solid red;">
		我是可编辑的div
	</div>
	<button onclick="pasteHtmlAtCaret('我是插入的内容')">插入</button>
</body>
<script type="text/javascript">
	
	function pasteHtmlAtCaret(html) {
     
     
    var sel, range;
    if (window.getSelection) {
     
     
        // IE9 and non-IE
        sel = window.getSelection();
        if (sel.getRangeAt && sel.rangeCount) {
     
     
            range = sel.getRangeAt(0);
            range.deleteContents();

            // Range.createContextualFragment() would be useful here but is
            // only relatively recently standardized and is not supported in
            // some browsers (IE9, for one)
            var el = document.createElement("div");
            el.innerHTML = html;
            var frag = document.createDocumentFragment(), node, lastNode;
            while ( (node = el.firstChild) ) {
     
     
                lastNode = frag.appendChild(node);
            }
            range.insertNode(frag);

            // Preserve the selection
            if (lastNode) {
     
     
                range = range.cloneRange();
                range.setStartAfter(lastNode);
                range.collapse(true);
                sel.removeAllRanges();
                sel.addRange(range);
            }
        }
    } else if (document.selection && document.selection.type != "Control") {
     
     
        // IE < 9
        document.selection.createRange().pasteHTML(html);
    }
}
</script>
</html>

方法二：可插入一段html字符串，可被解析

	<body>
		<div id="box" contentEditable>我是p标签的内容</div>
	</body>
	<script type="text/javascript">
		document.getElementById("box").onmouseup = function() {
     
     
			insertHtmlAtCursor("<strong>666</strong>")
		}

		//插入一个HTML字符串：
		function insertHtmlAtCursor(html) {
     
     
			var range, node;
				range = window.getSelection().getRangeAt(0);
				node = range.createContextualFragment(html);
				range.insertNode(node);
		}
	</script>

方法三： 插入一段文本

	<body>
		<div id="box" contentEditable>我是p标签的内容</div>
	</body>
	<script type="text/javascript">
		document.getElementById("box").onmouseup = function() {
     
     
			insertTextAtCursor("<strong>666</strong>")
		}

		function insertTextAtCursor(txt) {
     
     
			var sel = window.getSelection();
			var iEnd = sel.anchorOffset;
			var htmldata = sel.anchorNode.data;

			if(htmldata) {
     
     
				var finaldata = htmldata.substring(0, iEnd) + txt + htmldata.substring(iEnd);
				sel.anchorNode.textContent = finaldata
			} else {
     
     
				sel.anchorNode.textContent = txt
			}
		}
	</script>

方法四： 插入一个节点

	<body>
		<div id="box" contentEditable>我是p标签的内容</div>
	</body>
	<script type="text/javascript">
		document.getElementById("box").onmouseup = function() {
     
     
			insertTextAtCursor("<strong>666</strong>")
		}

		function insertTextAtCursor(text) {
     
     

			var sel = window.getSelection();
			if(sel.getRangeAt && sel.rangeCount) {
     
     
				var range = sel.getRangeAt(0);
				range.deleteContents();
				range.insertNode(document.createTextNode(text));

			}

		}
	</script>

总结了以上方式，大概能满足你插入的基本需求了

获取光标位置：

 console.log(window.getSelection().anchorOffset)  //起始点位置
 console.log(window.getSelection().focusOffset)   //末尾点位置

获取选中区域的文本：

document.onmouseup=function(){
    
    
			 console.log(window.getSelection().toString())
}

光标移动到最后：

	<body>
		<div id="box" contentEditable>我是p标签的内容</div>
	</body>
	<script type="text/javascript">
		document.getElementById("box").onmouseup = function() {
     
     
			set_focus(this)
		}

		//光标移动到最后
		function set_focus(el) {
     
     
			//	el.focus();
			//创建一个range范围对象
			var range = document.createRange();
			//用于设置 Range，使其包含一个 Node的内容。
			range.selectNodeContents(el);
			//将包含着的这段内容的光标设置到最后去，true 折叠到 Range 的 start 节点，false 折叠到 end 节点。如果省略，则默认为 false .
			range.collapse(false);
			var sel = window.getSelection();
			sel.removeAllRanges();
			sel.addRange(range);

		}
	</script>

记录光标和恢复光标：`通过一个例子演示`

	<body>
		<div id="box" contentEditable>我是p标签的内容</div>
		<button id="saveBtn">记录光标位置</button>
		<button id="restoreBtn">恢复光标位置</button>
	</body>
	<script type="text/javascript">
		
		//全局变量用来存放range变量，恢复的时候使用
		let range = null
		
		document.getElementById("saveBtn").onclick=function(){
     
     
			range = saveSelection()
		}
		document.getElementById("restoreBtn").onclick=function(){
     
     
			restoreSelection(range)
		}
		

		function saveSelection() {
     
     
			if(window.getSelection) {
     
     
				sel = window.getSelection();
				if(sel.getRangeAt && sel.rangeCount) {
     
     
					return sel.getRangeAt(0);
				}
			} else if(document.selection && document.selection.createRange) {
     
     
				return document.selection.createRange();
			}
			return null;
		}

		function restoreSelection(range) {
     
     
			if(range) {
     
     
				if(window.getSelection) {
     
     
					sel = window.getSelection();
					sel.removeAllRanges();
					sel.addRange(range);
				} else if(document.selection && range.select) {
     
     
					range.select();
				}
			}
		}
	</script>

先这么多，有新的需求或者想起来再补