如何通过JavaScript保存图像(从浏览器)

<input type="file" id="imageInput">

var fileInput = document.getElementById("imageInput");
var file = fileInput.files[0];

var reader = new FileReader();
reader.onload = function(e) {
  var imageData = e.target.result;
  // 图像数据处理代码
};
reader.readAsDataURL(file);

var img = new Image();
img.src = imageData;
img.onload = function() {
  // 图像加载完成后的处理代码
};

<canvas id="canvas"></canvas>

var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");

context.drawImage(img, 0, 0);

canvas.toBlob(function(blob) {
  var link = document.createElement("a");
  link.href = URL.createObjectURL(blob);
  link.download = "image.png";
  link.click();
});