js下载图片

downloadImg(url,name) {
      var image = new Image();
      image.crossOrigin = "Anonymous";
      image.onload = function() {
        var canvas = document.createElement("canvas");
        canvas.width = image.width;
        canvas.height = image.height;
        var context = canvas.getContext("2d");
        context.drawImage(image, 0, 0);
        var dataURL = canvas.toDataURL("image/png");
        var a = document.createElement("a");
        var event = new MouseEvent("click");
        a.download = name || "默认";
        a.href = dataURL;
        a.dispatchEvent(event);
      };
      image.src = url;
    }