lovecoding
/
W250511


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <ul id="list">
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
    <button id="btn">添加</button>
    <script>
        var oBtn = document.getElementById("btn");
        var oList = document.getElementById("list");
        var num = 3;

        oBtn.onclick = function(){
            // 创建元素
            var oLi = document.createElement("li");
            num++;
            oLi.innerText = num;
            // 将元素插入到页面中
            oList.append(oLi);
            // oList.appendChild(oLi);
        }
    </script>
</body>
</html>