问使用Ajax POST请求将图像和JSON数据发送到服务器？

EN

function getBase64Image(imgElem) {
// imgElem must be on the same server otherwise a cross-origin error will be thrown "SECURITY_ERR: DOM Exception 18"
    var canvas = document.createElement("canvas");
    canvas.width = imgElem.clientWidth;
    canvas.height = imgElem.clientHeight;
    var ctx = canvas.getContext("2d");
    ctx.drawImage(imgElem, 0, 0);
    var dataURL = canvas.toDataURL("image/png");
    return dataURL.replace(/^data:image\/(png|jpg);base64,/, "");
}

var file = $('.file-upload > input')[0].files[0];

function upload(file) {
  var reader = new FileReader();

  // when image data was read
  reader.onload = function(event) {
    // I usually remove the prefix to only keep data, but it depends on your server
    var data = event.target.result.replace("data:"+ file.type +";base64,", '');

    // make here your ajax call
    $.ajax({
      url: 'and_so_on',
      json: {
        data: data
      }
    });

  // read data from file
  reader.readAsDataURL(file);

var buffer = new Buffer(data, 'base64');