<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div class="app" contenteditable="true">
<span id="content">12345675345</span>
<p id="content2">12345675345</p>
</div>
<button id="btn">显示选中文字</button>
</body>
<script>
selction = window.getSelection();
const btn = document.querySelector('#btn');
const app = document.querySelector('.app');
const content = document.querySelector('#content');
const content2 = document.querySelector('#content2');
app.focus();
btn.onclick = function () {
let selction ,text;
console.log(selction.toString());//输出选中文字
alert(selction);
}
let range = selction.getRangeAt(0);
range.setStart(selction.anchorNode,selction.anchorOffset);
range.setEnd(selction.focusNode,selction.focusOffset+6);
selction.removeAllRanges();
selction.addRange(range);//主动添加选中文字
console.log(selction);
</script>
</html>
