js控制图片等比例缩放

function resizeImage(img, maxWidth, maxHeight) {
    let width = img.width;
    let height = img.height;

    if (width > height) {
        if (width > maxWidth) {
            height *= maxWidth / width;
            width = maxWidth;
        }
    } else {
        if (height > maxHeight) {
            width *= maxHeight / height;
            height = maxHeight;
        }
    }

    return { width: width, height: height };
}

// 使用示例
let img = new Image();
img.src = 'path_to_your_image.jpg';
img.onload = function() {
    let newSize = resizeImage(img, 300, 200); // 设置最大宽度和高度
    img.style.width = newSize.width + 'px';
    img.style.height = newSize.height + 'px';
};