function getFileSize(fileByte) {

       var fileSizeByte = fileByte;

       var fileSizeMsg = "";

       if(fileSizeByte < 1024){

           fileSizeMsg = fileSizeByte  + "B";

       }else if (fileSizeByte < 1048576) {

           fileSizeMsg = window.parseFloat(((fileSizeByte / 1024)).toFixed(2)) + "KB";

       }else if (fileSizeByte == 1048576) {

           fileSizeMsg = "1MB";

       }else if (fileSizeByte > 1048576 && fileSizeByte < 1073741824){

           fileSizeMsg = window.parseFloat(((fileSizeByte / (1024 * 1024))).toFixed(2)) + "MB";

       }else if (fileSizeByte > 1048576 && fileSizeByte == 1073741824){

           fileSizeMsg = "1GB";

       }else if (fileSizeByte > 1073741824 && fileSizeByte < 1099511627776){

           fileSizeMsg = window.parseFloat(((fileSizeByte / (1024 * 1024 * 1024))).toFixed(2)) + "GB";

       }else{

           fileSizeMsg = "文件超过1TB";

       }

       return fileSizeMsg;

     }