How to check if a cell in a certain column is empty?

pagente082993

Hello I am trying to disable tooltip if the cell is empty how can I make it? Here is my code

         "fnDrawCallback": function (oSettings) {
            $('#mtable tbody tr').each(function () {
                var sTitle;
                var nTds = $('td', this);
                var prnumber = $(nTds[6]).text();

                sTitle = prnumber;
                this.setAttribute('rel', 'tooltip');
                this.setAttribute('title', "<b>PR Number : </b>" + sTitle);
                $(this).tooltip({
                    html: true
                });
            });
          }