Jquery chained select box, how to disable blank option -

<select id="countryselect" name="country>     <option value="us">united states</option>     .     . </select>  <select id="cityselect" name="city"></select> 

this html code and

$.cityselect = function(){     var td= $('#countryselect').val();     $.ajax({         type: "post",         url: "action.php",         data: {'countrytd':td},         success: function(e){             $('#cityselect').html(e);         },     }); }; 

this chained select function. mysql process creating options in action.php.

here thing, when use function, result that

<select id="cityselect" name="city">     <option value></option> // empty value     <option value="1">new york</option>     <option value="2">broadway</option> </select> 

i dont want empty value because need information. there no empty value wrote anywhere. there no problem in php file because when changed this

$('#cityselect').html(e); 

to this

$('#cityselect').html('<option value="1">name</option>'); 

it adds blank value top anyway.

how can disable process or how can remove blank value after operation.

also when use 'e' comes success includes metatags , other head elements use language character set in action.php . how can clean these?

as @roasted stated, difficult figure out without code, should resolve @ least part of issue you:

first, note: of jquery 1.8 success callback method deprecated:

the jqxhr.success(), jqxhr.error(), , jqxhr.complete() callbacks deprecated of jquery 1.8. prepare code eventual removal, use jqxhr.done(), jqxhr.fail(), , jqxhr.always() instead.

here solution of problem. not solution of it, as, if getting blank value sql query, there problem query, database, or both. however, provide 'solution' front-end part of problem -> (this predicated on assumption php file builds relevant <option> elements <select> element):

$.cityselect = function(){ var td= $('#countryselect').val(); $.ajax({     type: "post",     url: "action.php",     data: {'countrytd':td},       }).done(function(data){            // better not use 'e' variable (can confusing)          if($(data).html().replace(/\s/g,'').length){           //there number of ways check          //(depends on expecting).         //  example used catch blank spaces                 $('#cityselect').html(data);            }     }) };