PHP：得到了一个json解析错误

Question

I want to import data from the database into my javascript code, using ajax through jQuery, but I got a json parse error and I really don't know what it does come from. Could you help me ?

The goal is to build buildings on a map, and i take the geometry elements such as coordinates and shape parameters from the database.

in the JS file, put:

 $.ajax({ 

  type: "GET",
  url: "ajax_processor.php",
  dataType : "html",

  error:function(msg, string){ 
     alert( "Error !: " + string );
  }

  success:function(returnData){ 

     var data = $.parseJSON(returnData); 

     for(var ID_geometryElement  in data) {
          addComp($data[bldg], 
                  $data[iZ], // zone where is the building
                  $data[iType], //type of the geometric element
                  $data[x0],
                  $data[y0],//coordinates top-left
                  $data[p], // geometric parameters
                  );
     }
   }
 });

});

in the PHP file:

try {
   $bdd = new PDO('mysql:host=localhost;dbname=building_geometry','admin','password');
}

 $reponse = $bdd->query('SELECT * FROM ID_GEOMETRYELEMENT');
 $donnees = $reponse->fetch(); 

  header('Content-Type: application/json'); 
  echo json_encode($response); 

  ?>  

Answer 1

You're trying to json_encode the database statement handle your query returned. That is NOT something you can encode. The code should be

echo json_encode($donnees);
                 ^^^^^^^^--- the actual data

If you'd done even the most basic debugging, e.g. console.log(returnData) in JS, you'd have seen you're not getting anything valid returned from the script.