图片下载-js实现

/**
 * 
 * @param {String} requestUrl 图片路径
 * @param {String} saveFileName 保存的图片名称
 * @param {String} fileFormat 图片格式 如：png, jpg, jpeg
 */
function imgDownload(requestUrl, saveFileName, fileFormat) {
  saveFileName = saveFileName || "image";
  fileFormat = fileFormat || "png";
  const img = document.createElement('img');
  img.src = requestUrl;
  img.setAttribute("crossOrigin", "Anonymous");
  img.onload = function () {
    const a = document.createElement("a");
    a.setAttribute("download", saveFileName);
    a.href = getImageDataURL(img);
    a.click();
  };
  function getImageDataURL(img) {
    let canvas, ctx;
    const width = img.width;
    const height = img.height;
    canvas = document.createElement("canvas");
    canvas.width = width;
    canvas.height = height;
    ctx = canvas.getContext("2d");
    ctx.drawImage(img, 0, 0, img.width, img.height);
    return canvas.toDataURL("image/" + fileFormat, 1);
  }
}

 

有跨越问题看这篇文章：

https://blog.youkuaiyun.com/weixin_40647516/article/details/102660374