Giving a simple table like this

<table id="exampleTable" class="table hover nowrap">
   <thead>
      <tr>
         <th>Id</th>
         <th>Name</th>
      </tr>
   </thead></table>

Also, using the jQuery Datatable plugin and making the rows selectable, like in this example. The Javascript goes like this:

var exampleTable = $("#exampleTable").DataTable(
                    {
                        "bDestroy": true,
                        "lengthChange": false,
                        "bPaginate": false
                    });

$('#exampleTable tbody').on( 'click', 'tr', function () {
        if ( $(this).hasClass('selected') ) {
            $(this).removeClass('selected');
        }
        else {
            $('#exampleTable tr.selected').removeClass('selected');
            $(this).addClass('selected');
        }
    } );

So, when the table is empty, it shows a selectable row which says something like:

No data available in table

How to detect the table is empty and not allow selection on that kind of "message rows"?

Here is a fiddle with the code.

you can check if there is td with the class dataTables_empty like this:

$('#exampleTable tbody').on( 'click', 'tr', function () {
        if ( $(this).hasClass('selected')) {
            $(this).removeClass('selected');
        }
        else if(! $(this).find('td.dataTables_empty').length){
            $('#exampleTable').DataTable().rows().nodes().each(function(){
               $(this).removeClass('selected');
            });
            $(this).addClass('selected');
        }
    } );

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