lovecoding
/
class


			
				
					
						
						
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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>
    <style>
        .box {
            width: 200px;
            height: 200px;
            background: #f00;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <button id="btn1">显示</button>
    <button id="btn2">隐藏</button>
    <script>
        // 需求：改变盒子的大小及颜色
        // 显示在浏览器五秒后改变
        var box = document.querySelector(".box");
        var btn1 = document.getElementById("btn1");
        var btn2 = document.getElementById("btn2");
        setTimeout(()=>{
            console.log(box);
            box.style.width = "300px";
            box.style.height = "300px";
            box.style.background = "#00f";
        },5000)
        btn1.onclick = function() {
            box.style.display = "block";
        }
        btn2.onclick = function() {
            box.style.display = "none";
        }
    </script>
</body>
</html>