JavaScript image preview and upload (IE compatible)

var dailiApply = {

   change: function (evt) {
    ();
    var pic = ("preview"),
     file = ("f");

    var ext=((".")+1).toLowerCase();
    // gif cannot be displayed in IE browser for the time being    if(ext!='png'&&ext!='jpg'&&ext!='jpeg'){
     alert("The image format must be in png or jpg or jpeg format!");
     return;
    }
    var isIE = (/MSIE/)!= null,
     isIE6 = (/MSIE 6.0/)!= null;

    if(isIE) {
     ();
     var reallocalpath = ().text;

     // IE6 browser sets the src of img to the local path to directly display pictures     if (isIE6) {
       = reallocalpath;
     }else {
      // Due to security issues, IE is not able to display local pictures directly by setting img's src, but it can be achieved through filters       = "progid:(sizingMethod='image',src=\"" + reallocalpath + "\")";
      // Set the src of img to a transparent picture encoded by base64. Cancel display the default picture of the browser       = 'data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==';
     }
    }else {
     var file_arr = ;
     var ul = $(".weui_uploader_files");
     if(file_arr.length < 7) {
      for(var key in file_arr) {
       if(file_arr.hasOwnProperty(key)) {
        var f = file_arr[key];
        var url = (f);
        var reader = new FileReader();
        (f);
        (f);
        n +=1;
        if(n < 7) {
         reader._onload = function(e) {

          // Stitch together the html that displays the preview image          var list = $("<li class='weui_uploader_file' style='position: relative'>" +
           "<img id='preview" + n + "' class=preview_li' style='width: 100%;height: 100%'>" +
           "<span id='delImg" + n+ "' style='position: absolute; top: 0; right: 4px; color: #e4007f'>X</span></li>");
          (list);
          // Put the converted image address in img          var pic = ('preview' + n);
          // = ;
          =url;
          (f, .7,undefined);
          //(f);
          ('delImg' + n).addEventListener("click", function () {
           $(this).parent().remove();
           --n;
          });

         };
         reader._onload();
        }else {
         $.alert("Upload up to 6 pictures");
         n = 6;
        }
       }
      }
     }else {
      $.alert("Upload up to 6 pictures");
     }
    }
    return false;
   },
   /**
     * @param {Object} f input selected image Required
     * @param {String} quality The quality of image compression [0, 1]
     * @param {String} output_img_type The type of output image
     */
   compress: function (f, quality, output_img_type) {
    var mime_type = "image/jpeg";
    if(output_img_type!=undefined && output_img_type=="image/png"){
     mime_type = "image/png";
    }
    createImageBitmap(f).then(function(imageBitmap) {
     var max = 1000; // Set maximum resolution     var c_w = '';
     var c_h = '';
     var width = ;
     var height = ;
     // Scale scale     if (width > max || height > max) {
      if (width > height) {
       c_w = max;
       c_h = max * height / width;
      } else {
       c_h = max;
       c_w = max * width / height;
      }
     }else {  // No zoom      c_w = width;
      c_h = height;
     }

     var canvas = ('canvas');
      = c_w;
      = c_h;
     var ctx = ('2d');
     (imageBitmap,0,0, width, height, 0, 0, c_w, c_h);
     (function(blob){
      (blob);
     },mime_type, quality);
    });
   },
   submit: function () {
    var content = $(".weui_textarea").val().trim();
    var xhr = new XMLHttpRequest();
    var fd = new FormData(('uploadForm'));
    $.each(images,function(i,e){
     ("images", e);
    });
    ("remark", content);
    ("substationproxyId", 8);
    (images);
    (fd);
    if(content) {
     $.ajax({
      url: ,
      type: "POST",
      data: fd,

      processData: false, // tell jQuery not to process the data
      contentType: false, // tell jQuery not to set contentType
      beforeSend: function (xhr) {
       $.showLoading();
       $(this).prop("disabled", true)
      },
      success: function (json) {
       (json);
       $.hideLoading();
       $(this).prop("disabled", false);
       if( == 0) {
        $.alert("Save successfully", function () {
         ();
        })
       }else if( == "-101") {
        $.alert('Error:' +, function () {
          = ;
        });
       }else {
        $.alert(, function () {

        })
       }
      }
     });
    }else {
     $.alert('Please enter content');
    }

   }

  };