anchor.diff:  					    var fileID = document.getElementById("addCommentFileID").value;
   					    var comment=document.getElementById("userComment").value;
   					    document.getElementById("userComment").value = "";
  +
  +					    if(comment =="" || comment == null) return;
  +					    
   					    $.ajax({
   				            type : "POST",
   				            url : "AddComment",
  -				            
   				            data : { fileID: fileID, comment: comment },
   				            success : function(data) {
   				                $(".modal-body").html(data);
  
positive.code: 			<form id="addCommentForm">
  				<input type= "hidden" id="addCommentFileID">
  				<div class="form-group">
  					<input type="text" class="form-control" id="userComment" required />
  				</div>
  				<div class="form-group">
  					<button type="button" name="addCommentBtn" id="addCommentBtn" class="btn btn-success">Comment</button>
  
negative.code:             success : function(data) {
                  $(".modal-body").html(data);
              	var fileName = document.getElementById("fileURL").innerText;
              	document.getElementById("myModalLabel").innerText = title;
              }
          });
  	});    
  