js等比缩放

function resizeImage(imageElement, containerElement) {
    const containerWidth = containerElement.clientWidth;
    const containerHeight = containerElement.clientHeight;
    const imageWidth = imageElement.naturalWidth;
    const imageHeight = imageElement.naturalHeight;

    let newWidth, newHeight;

    if (imageWidth / containerWidth > imageHeight / containerHeight) {
        // 图像更宽，按高度缩放
        newHeight = containerHeight;
        newWidth = (imageWidth / imageHeight) * newHeight;
    } else {
        // 图像更高，按宽度缩放
        newWidth = containerWidth;
        newHeight = (imageHeight / imageWidth) * newWidth;
    }

    imageElement.style.width = `${newWidth}px`;
    imageElement.style.height = `${newHeight}px`;
}

// 使用示例
const img = document.getElementById('myImage');
const container = document.getElementById('imageContainer');
resizeImage(img, container);

img.onload = function() {
    resizeImage(img, container);
};

window.addEventListener('resize', () => {
    resizeImage(img, container);
});