Jquery + Ajax, Params has data but response says no data

问题

I have the following script:

$("#spid").blur(function() {
    $.ajax({
       url: 'getsponsor.php',
       type: "POST",
       dataType:'json',
       data: ({ spid: $("#spid").val() }) ,
       contentType: 'application/json; charset=utf-8',
       success: function (result) {
           $("#sponname").text(result);
       },
       error: function () {
           $("#sponname").text("Cannot fetch the sponsor name.");
       }
   }); 
});

Note: #sponname is a label tag.

Following is the php code of getsponsor.php:

if(!isset($_POST['spid']) || empty($_POST['spid']))
    echo json_encode("No Data");
else {
    $spid=$_POST['spid'];
    $stmt = $con->prepare("SELECT name FROM users WHERE id=?");
    $stmt->bind_param("s",$spid);
    $stmt->execute();
    $stmt = $stmt->get_result();
    if ($stmt->num_rows >0) {
        $row = $stmt->fetch_object();
        echo json_encode($row->name);
    }
    else {
        echo json_encode("No Records");
    }
}

When I Inspect the page and goto Network->Params, I get the right value from the textbox:

spid=1125468

But, when I go to Network->Response, I get the following message

"No Data"

Please tell what wrong I am doing?

回答1:

Get rid of this line:

contentType: 'application/json; charset=utf-8',

The data is being sent URL-encoded, not as JSON. jQuery will send the correct Content-type header by itself.

来源：https://stackoverflow.com/questions/52111576/jquery-ajax-params-has-data-but-response-says-no-data