AJAX Get无效

Question

I'm attempting to pull data from a mysql server with AJAX. This is the AJAX call:

function getAllTasks()
        {
            alert("Getting all tasks");

            $.ajax({
              type: "get",
              url: "ajax.php",
              dataType: "json",
              data: data,
              async: false,
              success: function(data){
                   alert('hi!');
                   //perform operation
                },
                error: function() {
                  alert('Error occurs!');
                }
            });
        }

and this is the PHP it's supposed to run:

header('Content-Type: application/json');



$conn = new mysqli('localhost', 'projectAdmin', 'admin', 'to_do_list')
    or die('Error connection to database');

    getAllTasks($conn);




function getAllTasks($conn)
{
$query = "SELECT * FROM tasks WHERE ID=1";

$result = mysqli_query($conn, $query);

while($row = $result->fetch_assoc())
{
    $tasks[] = $row;
}

echo json_encode($tasks);

}

It's not working. When I run the PHP alone, it works fine, and returns a JSON string in the browser (chrome). When I run the AJAX, nothing happens. I get the "getting all tasks" alert, and then it just doesn't work. The AJAX is called from the $(document).ready() function.

I don't know where I'm going wrong, I've looked at a bunch of posts on here and my AJAX code looks next to identical. Is it an issue with json_encode? The AJAX? Help, please.

Answer 1

Here:

data: data,

It looks that the data variable is undefined. Also I would recommend you removing the async: false option in order to make an asynchronous request instead of blocking the UI.

Looking at the Console in your browser might also reveal some potential problems with your code.