When you click on the remove button, use javascript to read the data into an array. Remove the last line and write it back.

Thanks Sojan.

This I am sure your logic would work.

However, I was able to do it without using the array. I am copyimg the code, I used, here.

Though, let me acknowledge, I got the hint from your suggestion.

Hence, thanks all the same, I appreciate your time and effort. 

I was able to do the trick using the following code -

function RemoveLastLine()
{
     var OldData = NWF$('#'+ fldMultiLine).val();   

     if(OldData.lastIndexOf("
")>0)
    {
          var TruncatedData = OldData.substring(0, OldData.lastIndexOf("
"));
          NWF$('#'+ fldMultiLine).val('');
          NWF$('#'+ fldMultiLine).val(TruncatedData);
      }
     else
     {
          NWF$('#'+ fldMultiLine).val('');
      }
 }

You can also try RegEx to remove the last line.