$(document).on('ready',function (){
        alert("hola!");
     $.post("scripts/json_p.asp?m=prv",
        function(data) {
          var $select = $("#prv_codigo");
            $.each(data, function(id, name) {
              $select.append('<option value=' + data.id + '>' + data.name + '</option>');
             });
         });
     });