<!DOCTYPE html>
<html>
<head>
<title>W3.CSS(w3cschool.cn)</title>
<meta name="viewport" content="width=device-width, initial-scale=1" charset="UTF-8">
<link rel="stylesheet" href="https://7npmedia.w3cschool.cn/w3.css">
</head>
<body>
<div class="w3-container">
<h2>带标签的动态进度栏</h2>
<p>居中标签:</p>
<div class="w3-light-grey">
<div id="myBar" class="w3-container w3-green w3-center" style="width:20%">20%</div>
</div>
<br>
<button class="w3-button w3-green" onclick="move()">点击我</button>
</div>
<script>
function move() {
var elem = document.getElementById("myBar");
var width = 20;
var id = setInterval(frame, 10);
function frame() {
if (width >= 100) {
clearInterval(id);
} else {
width++;
elem.style.width = width + '%';
elem.innerHTML = width * 1 + '%';
}