javascript - Populate select menu onChange -

i have bootstrap select menu want populate onchange select menu. think have problems returning data php.

select menu:

            <div class="col-md-6" style="width:100%;margin-bottom: 10px;">                 <div class="input-group" style="width:100%;">                     <span style="width:50%;" class="input-group-addon" id="basic-addon1">municipality *</span>                     <select class="selectpicker" name="object_municipality" id="object_municipality">                         <option value="0" selected="selected" >municipality *</option>                                               </select>                 </div>             </div> 

javascript function (called onchange select menu) populate select menu:

function populate_obcina(value) { if (window.xmlhttprequest) {     xmlhttp=new xmlhttprequest();   } else {     xmlhttp=new activexobject("microsoft.xmlhttp");   }   xmlhttp.onreadystatechange=function() {     if (xmlhttp.readystate==4 && xmlhttp.status==200) {       document.getelementbyid("object_municipality").innerhtml=xmlhttp.responsetext;     }   }   xmlhttp.open("get","get_municipality.php?q="+value,true);   xmlhttp.send(); }    

my get_municipality.php file:

    <?php     require_once 'functions.php';     $conn = dbconnect();      $q =($_get['q']);          $municipality = mysqli_query($conn, "select id,municipality municipalities  `region`='".$q."'") or die(file_put_contents('error_querry.txt', print_r("error: " . mysqli_error($conn), true)));      while ($row = mysqli_fetch_array($municipality, mysqli_assoc)) {        $fp = fopen("while_loop.txt", "a") or die("couldn't open log file writing.");       fwrite($fp, php_eol .'<option value="'.$row['id'].'">'.$row['municipality'].'</option>');       fflush($fp);       fclose($fp);              //in while_loop.txt lines this:       //<option value="1">chicago</option>       //so guess problem way returning results        echo '<option value="'.$row['id'].'">'.$row['municipality'].'</option>';     }      mysqli_close($conn);     ?> 

this return get:

<option value="1">chicago</option><option value="2">la</option><option value="3">california</option> 

i did kind of job, did differently since had able populate many kinds of selects, on events, pre-chosen data or not, ... jquery, bootstrap, & on...

select html :

<div class="col-md-6" style="width:100%;margin-bottom: 10px;">     <div class="input-group" style="width:100%;">         <span style="width:50%;" class="input-group-addon" id="basic-addon1">municipality *</span>         <select class="selectpicker" name="object_municipality" id="object_municipality">             <option value="0" selected="selected" >municipality *</option>                                   </select>     </div> </div> 

javascript/jquery populate "class", make file called populatelist.js :

function populatelist(){ }  populatelist.municipality = function(element,choice){     $(document).ready(function(){         $.ajax({             type : 'post',             url : './getmunicipalitieschoice.php',             data  : {'choice':choice},             datatype : 'json',             error : function(response){                 alert('something went wrong');             },             success : function(response){                 element.html(response);             }         });     }); }; 

jquery on change event :

$(document).on('change','#listfiringtheevent',function(){     //call populate function here     populatelist.municipality('#object_municipality',$(this).val()); }); 

php getmunicipalitieschoice.php :

<?php     require_once 'functions.php';     if(isset($_post['choice'])){         $conn = dbconnect();         $q = $_post['choice'];         $result = '';         $municipality = mysqli_query($conn, "select id,municipality municipalities  `region`='".$q."'") or die(file_put_contents('error_querry.txt', print_r("error: " . mysqli_error($conn), true)));          while ($row = mysqli_fetch_array($municipality, mysqli_assoc)) {             $fp = fopen("while_loop.txt", "a") or die("couldn't open log file writing.");             fwrite($fp, php_eol .'<option value="'.$row['id'].'">'.$row['municipality'].'</option>');             fflush($fp);             fclose($fp);             $result.='<option value="'.$row['id'].'">'.$row['municipality'].'</option>';         }         mysqli_close($conn);         echo json_encode($result);     }else{         //if you're here, that's because file has been called "invalid" choice (not set)     } ?> 

now, said, if have other lists fill, add functions in populatelist.js file this, example, function fills list municipalities, not depending on choice :

populatelist.municipalities = function(element){     $(document).ready(function(){         $.ajax({             type : 'post',             url : './getmunicipalities.php',             datatype : 'json',             error : function(response){},             success : function(response){                 element.html(response);             }         });     }); }; 

or example fill "cities" list when chose "municipality" :

populatelist.citiesonmunicipality= function(element,municipality){     $(document).ready(function(){         $.ajax({             type : 'post',             url : './getcitiesonmunicipality.php',             data : {'municipality':municipality},             datatype : 'json',             error : function(response){},             success : function(response){                 element.html(response);             }         });     }); }; 

in example here, assume html , php code "good".

but (for php) have use prepared statements...

hope helps!