Json不从PHP接收数据

Question

Hi I pass an array from php to another to used it on a javascript function using json, but not return nothing, gives me "null" all time.

php code

function getParents($id_child){
include "conexion.php";
$query = $conexion->query('SELECT person_id FROM children WHERE children_id='.$id_child.';');
$query->execute();

while ($res = $query->fetch()) {
    $id_parents[] = $res[0]; //family_id
}
return $id_parents;
echo json_encode($id_parents);


}
getParents($_POST['id_child']);

Php who takes the json:

    <?php
$json_data=json_encode($id_parents);
?>
function sacarPadres(id_child){

    $.ajax({
            data:  {"id_child" : id_child,
            },
            url:   'php/functions_sql.php',
            type:  'post',
            success:  function(output) {

              }
    });
    var an_obj= "<?php echo $json_data;?>";
alert(an_obj); // always null 

}
<div id="form">
<FORM NAME=form1>
    <INPUT TYPE='button' NAME='myFamily' value='add new family' onclick="sacarPadres(70);">
</FORM>

Answer 1

After return type everything is vanish

just remove return type

//return $id_parents;
  echo json_encode($id_parents);

Updated

function getParents($id_child){
include "conexion.php";
$query = $conexion->query('SELECT person_id FROM children WHERE children_id='.$id_child.';');
$query->execute();

while ($res = $query->fetch()) {
    $id_parents[] = $res[0]; //family_id
}

return json_encode($id_parents);


}
echo $val=getParents($_POST['id_child']);

Ajax

$.ajax({
            data:  {"id_child" : id_child,
            },
            url:   'php/functions_sql.php',
            type:  'post',
            success:  function(output) {
                      alert(output);//alert here
              }
    });

Answer 2

The return statement causes the program to exit the function. All statements after return will not be executed. Move return to the end of the function or remove at all.