Ajax POST方法在PHP中不起作用，但是GET在起作用

Question

I am trying to send using Ajax a POST request to php.

If I use GET it works fine, but with POST the data I receive in php is empty. I'm sending data as a json.

This is what the js code looks like:

$.ajax(
        {
            type: 'POST',
            url: 'php/GiveItBack.php',
            contentType: "json",
            data: {
                word: 'abc'
            },
            success: function (json) {
                alert(json);
            },
            error: function (jqXHR, textStatus, errorThrown) { alert('ERROR: ' + errorThrown); }
        });

This is the php/GiveItBack.php file

<?php

$x = $_GET['word'];
echo 'Get: ' . $x;

$x = $_POST['word'];
echo '; Post: ' . $x;

$x = $_REQUEST['word'];
echo '; Request: ' . $x . ';';

?>

With this code, the message in the alert window looks like this:

Get: ; Post: ; Request: ;

If I replace type: 'POST' in the js file with type: 'GET' this is the result I get in the alert window (as I was expecting to see):

Get: abc; Post: ; Request: abc;

I can't see what I'm missing here. Is something wrong in the code or is any special setting I need to do for this to work.

By the way I am using: jquery-2.2.4.min and php v5.6 and XAMPP v3.2.2.

Thank you.

Answer 1

The content type was not correct, need to use contentType: "application/x-www-form-urlencoded" OR 'Content-Type': 'application/json'

   $.ajax(
    {
        type: 'POST',
        url: 'php/GiveItBack.php',
        contentType: "application/x-www-form-urlencoded",
        data: {
            word: 'abc'
        },
        success: function (json) {
            alert(json);
        },
        error: function (jqXHR, textStatus, errorThrown) { alert('ERROR: ' + errorThrown); }
    });

Answer 2

contentType: "json",

You content type is wrong here. If you want to receive it the way you are trying, you should use application/x-www-form-urlencoded .

If you still want to stick within JSON, you will have to json_decode your PHP input:

$json = file_get_contents('php://input');
$obj = json_decode($json, TRUE);

Answer 3

$.ajax(
    {
        method: 'POST',
        url: 'php/GiveItBack.php',
        data: {
            word: 'abc'
        },
        success: function (json) {
            alert(json);
        },
        error: function (jqXHR, textStatus, errorThrown) { alert('ERROR: ' + errorThrown); }
    });

Answer 4

Remove contentType: json and you should be able to use the $_POST superblogal array. If you use contentType: json the object containing the parameters is converted into a string and sent over to the server. To get the string you will need to use

file_get_contents('php://input');

This happens because $_POST only contains data sent along with the following headers:

• application/x-www-form-urlencoded
• multipart/form-data-encoded

When you set contentType: json , jQuery adds the application/json header to the request which is not supported by $_POST so the JSON string is treated as raw input and therefore you need to use the php://input stream to retrieve it

Answer 5

Ajax Data Remove the contentType: json :

$.ajax(
        {
            type: 'POST',
            url: 'php/GiveItBack.php',

        data: {
            word: 'abc'
        },
        success: function (json) {
            alert(json);
        },
        error: function (jqXHR, textStatus, errorThrown) { alert('ERROR: ' + errorThrown); }
    });