如果图像的尺寸是百分比,我如何保留图像的纵横比？

img {
  width: 100%;
  height: auto;
}

<img src="your-image-source.jpg" width="100%" height="auto" alt="Your image description">

function resizeImage(img) {
  img.style.width = "100%";
  img.style.height = "auto";
}

// 获取图像元素
var img = document.getElementById("your-image-id");

// 调整图像尺寸
resizeImage(img);