<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> .box { width: 200px; height: 200px; background-color: gold; position: absolute; } </style> <script type="application/javascript"> window.onload = function () { var box1 = document.getElementById(‘box‘); var speed = 5; var ileft = 0; var timer = setInterval(function () { ileft += speed; box1.style.left = ileft + ‘px‘; if (ileft > 800){ speed = -5; } if (ileft < 0){ speed = 5; } },30); } </script> </head> <body> <div class="box" id="box"></div> </body> </html>
原文：https://www.cnblogs.com/lurj/p/12463142.html