getting data from query sql database to javascript

Question

I have a problem with my code.
case like this:
I have a dropdown, if selected "personal" it appeared the new dropdown that contains the data that is retrieved from a database query, if selected "public", then the dropdown disappear.
HTML code like this:

<select name="use" class="dropdown" id="sender" onChange='changeSend()'>
     <option value=1>Public</option>
     <option value=0>Personal</option>
</select>

<div id='send2'></div>

Query like this:

<?php
    $query = mysql_query("select * from data where id_user = '$id_user' order by date asc");
    $i = 0;
    $id = array();
    $name = array();
    while($data = mysql_fetch_array($query)){
       //id from result database query
       $id[$i] = $data['id'];
       //name from result database query
       $name[$i] = $data['name'];
       $i++;
    }
?>

JavaScript code like this:

function changeSend() {
   var selectBox = document.getElementById("sender");
   var selectedValue = selectBox.options[selectBox.selectedIndex].value;
   if (selectedValue==0) {
       $('#send2').html("<select class='dropdown'><option value='-id from result database-'>-name from result database query-</option></select>");
   } else { 
    $('#send2').html('');
   }
}

I dont know how to send value/result ($id[0],$name[0],$id[1],$name[1], etc..) to javascript code(value and name in select options).

Answer 1

In javascript you have to make an ajax call to your php file:

var xmlhttp;
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("send2").innerHTML=xmlhttp.responseText;
    }
  }
xmlhttp.open("GET","yourFile.php",true);
xmlhttp.send();

And in your php file you have to echo your data in JSON format:

echo json_encode(array('id'=>$id,'name'=>$name));

UPDATE in your case use the following code: (not tested)

php code:

<?php
    $query = mysql_query("select * from data where id_user = '$id_user' order by date asc");
    $i = 0;
    $options = array();
    while($data = mysql_fetch_array($query)){
       $options[$data['id']] =  $data['name'];
    }
    echo json_encode($options);
?>

javascript code:

var xmlhttp;
if (window.XMLHttpRequest){// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
}
else{// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
  if (xmlhttp.readyState==4 && xmlhttp.status==200){
      var response = JSON.parse(xmlhttp.responseText);
      var select = '<select class='dropdown'>';

      for( var index in response ){
          select = select + "<option value='"+ index +"'>"+response[index]+"</option>";
      }
      select += "</select>";
      document.getElementById("send2").innerHTML= select;
  }
}
function changeSend() {
   var selectBox = document.getElementById("sender");
   var selectedValue = selectBox.options[selectBox.selectedIndex].value;
   if (selectedValue==0) {
       xmlhttp.open("GET","yourFile.php",true);
       xmlhttp.send();
   } 
   else { 
     $('#send2').html('');
   }
}

USING jQuery

javascript code:

function changeSend() {
   var selectBox = document.getElementById("sender");
   var selectedValue = selectBox.options[selectBox.selectedIndex].value;
   if (selectedValue==0) {

       $.get("yourFile.php", function(data){
           var response = JSON.parse(data);
           var select = '<select class='dropdown'>';

           for( var index in response ){
               select = select + "<option value='"+ index +"'>"+response[index]+"</option>";
           }
           select += "</select>";

           $("#send2").html(select);
       });

   } 
   else { 
     $('#send2').html('');
   }
}