I want to show data from database into ajax.

function Data_Table() {
  $.ajax( {
    url: "<?php echo site_url('admin-spot/company/FieldTable')?>", type: "GET", dataType: "JSON", success: function(data) {
      $('#map').dataSrc(data.map);
    }
  }
  );
}

<iframe id="map" src="" frameborder="0" style="width: 100%; height: 300px;" allowfullscreen></iframe>

</div>

As far as i understand from your hard to judge description and the comments section, you are trying to set the src attribute of the iframe with the googlemap link in the ajax success function and the src is coming from server-side, if this is it you have to use .prop to assign the src which should be a URL

change your function to the following

 function Data_Table() {

        $.ajax({
            url: "<?php echo site_url('admin-spot/company/FieldTable')?>",
            type: "GET",
            dataType: "JSON",
            success: function (data) {

                $('#map').prop('src',
                    data.map
                );
            }
        });
    }

You can use .load() method here the jquery API jquery API

Javascript

Use simple

$("#result").load("ajax/test.html");

or with a callback

$("#result").load("ajax/test.html", function() {
    alert( "Load was performed." );
});