lovecoding
/
web0715


			
				
					
						
						
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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: 50px;
            background-color: red;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <script>
        var oBox = document.getElementsByClassName("box")[0];
        
        // setTimeout(function(){
        //     oBox.style.width = "400px"
        // },2000)

        // offsetWidth 获取元素的宽度
        // offsetHeight 获取元素高度
        setInterval(function(){
            oBox.style.width = oBox.offsetWidth - 10 +"px";
        },16)
    </script>
</body>
</html>