Befor uploading Images to Server I want to get the height and width of Images. To do it, I use FileReader.

Code:
  var f = files[i];
  //Item from input files
  var oFReader = new window.FileReader();
  oFReader.readAsDataURL(f);
  oFReader.onload = function (oFrEvent) {
      var res = oFrEvent.target.result;
      var img = new Image();
      img.onload = function () {
         imgList.push({width:img.width,
...