js怎么修改背景图片

我给一个div盒子设置了一个背景图片，想用js修改背景图片的路径，但不知道格式
工具用的是VS Code


<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <!-- <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script> -->
    <title>document</title>
    <style>
      #banner {
        width: 200px;
        height: 200px;
        background-color: lawngreen;
      }
    </style>
  </head>
  <body>
    <div id="banner"></div>
    <script type="text/javascript">
      let banner = document.getElementById("banner");
      banner.onclick = function () {
        banner.style.backgroundImage =
          "url('../image/1308c9a644eaade636f4b5bf20bca54.jpg')";
      };
    </script>
  </body>
</html>

banner_pic.style.backgroundImage="url(../image/banner"+i+".jpg)";//改变背景图片