Read data from mysql php jquery ajax - php

Question

I need to read data from my web page with jquery + ajax
This is my function:
public function getvalueshahr()
{
if($_POST['ostan']!=0){
$db= JFactory::getDbo();
$query=$db->getQuery(TRUE);
$query->select('id,title')->from('#__categories')->
where($db->quoteName('parent_id').'='.$db->quote($_POST['ostan']));
$db->setQuery($query);
$res=$db->loadObjectList();
echo $db->getErrorMsg();
echo json_encode($res);}
}
I can read data with c# like this:
But my ajax method is not working. Here is the method:
$.ajax({
type: "POST",
url: "www.mysite.net/index.php?task=shahrestan.getvalueshahr",
data: "{ostan=77}",
dataType: "json",
success: function (result)
{
var d = $.parseJSON(result);
$.each(d, function (i, field)
{
$("#output").append("id: " + field.id + " title: " +
field.title+"br/>");
});
},
error: function (e)
{
alert("error:" + e.responseText);
}
});
The method returns nothing.

Answer 1

You're sending a string instead of an object in your ajax-request. Try changing :
data: "{ostan=77}"
to
data: { ostan: 77 }
And you should set the content type before echoing the results in PHP:
header('Content-Type: application/json');
echo json_encode($res);
Now you don't need $.parseJSON in the JS-code. You will get a json-object straight away.

Answer 2

First of all you send a wrong data to the server. You have to rewrite part of your code like this:
data: {ostan: 77},
or
data: "ostan=77",
The second problem is you get a result as a json object on the success method, but you try to parse it again to the json object. So remove this line from your code:
var d = $.parseJSON(result);
Finally your ajax function should looks like this:
$.ajax({
type: "POST",
url: "www.mysite.net/index.php?task=shahrestan.getvalueshahr",
data: {ostan: 77},
dataType: "json",
success: function (result)
{
$.each(result, function (i, field)
{
$("#output").append("id: " + field.id + " title: " +
field.title+"br/>");
});
},
error: function (e)
{
alert("error:" + e.responseText);
}
});

Answer 3

If you are loading data from you mysql-database you eventually have to convert these data because it is not stored as utf-8 converted. This piece of code convert given object to UTF-8: mb_convert_encoding(database-entry,'UTF-8');