jQuery获取file控件中图片的宽高与大小

var _URL = window.URL || window.webkitURL;
$("#file").change(function (e) {
  var file, img;
  if ((file = this.files[0])) {
    img = new Image();
    img.onload = function () {
      alert(this.width + " " + this.height);
    };
    img.src = _URL.createObjectURL(file);
  }
});

//获取input图片宽高和大小
function getImageWidthAndHeight(id, callback) {
  var _URL = window.URL || window.webkitURL;
  $("#" + id).change(function (e) {
    var file, img;
    if ((file = this.files[0])) {
      img = new Image();
      img.onload = function () {
        callback && callback({"width": this.width, "height": this.height, "filesize": file.size});
      };
      img.src = _URL.createObjectURL(file);
    }
  });
}

(function () {
  //省略其他代码
  getImageWidthAndHeight('image_file', function (obj) {
   if (obj.width != 843 || obj.height != 1038) {
    $.messager.alert('操作提示', '弹窗图片宽高必须是843*1038px');
   }
  });
})(jQuery)