lovecoding
/
VIP32


			
				
					
						
						
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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: 300px;
            height: 300px;
            background: #00f;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <br><br>
    <button id="btn1">放大</button>
    <br><br>
    <button id="btn2">缩小</button>
    <script>
        var box = document.querySelector(".box")
        var btn1 = document.getElementById("btn1");
        var btn2 = document.getElementById("btn2");
        btn1.onclick = function() {
           var timer = setInterval(function(){
                if(box.offsetWidth >= 500) {
                    clearInterval(timer);
                } else {
                    box.style.width = box.offsetWidth + 5 + 'px';
                }
            },50)
        }

        btn2.onclick = function() {
            var timer = setInterval(function(){
                if(box.offsetWidth <= 300) {
                    clearInterval(timer)
                } else {
                    box.style.width = box.offsetWidth - 5 + 'px';
                }
            },100);
        }
    </script>
</body>
</html>