将JSON从jQuery发布到PHP

Question

I would like to send a data via jQuery ajax function to the PHP script and receive a response - success or failure. The code I am using:

JavaScript:

$.ajax({
    type: 'POST',
    url: 'foo.php',
    dataType: 'json',
    data: {
        foo: 'foo'
    },
    success: function (response) {
        ...
    },
    error: function (response) {
        ...
    }
});

PHP:

<?php
header("Content-Type: text/json");
echo $_POST['foo']
?>

However this always return error, because of header("Content-Type: text/json");.

What is done wrong here?

Answer 1

This would handle the errors correctly server side.

<?php
    if(isset($_POST['foo']){
        header('Content-Type: application/json');

        $foo = array(
            "foo" => $_POST['foo'];
        );
        echo json_encode($foo);
    } else {
        header('HTTP/1.0 400 Bad Request');
    }
?>