Question

JavaScript

$.ajax({
    type : 'POST',
    url : 'post.php',           
    data: dataString,
    success:function (data) {
        if (data==null) { alert("darnit!!!!");}    
            //$("#response").append(data);
            alert(dataString);
        }          
    });     
});

in PHP file just a simple

print_r($_REQUEST);

Also tried

echo "got iT!";

But nothing, been looking of over tried differant things but no luck
first //alert (dataString); works
but after the success:function (data) I don’t get any alerts – no response within the page!

What am I doing wrong?

Answer 1

There’s a SyntaxError in your snippet. I’m not sure if that’s also in your real code.

Be sure to use json_encode in your PHP file and dataType: 'json' in jQuery.ajax. And always use an error callback as well. You don’t want your application to become indefinitely frozen if something fails.

Something like this:

$.ajax({
    url: 'api.php',        
    data: {
        action: 'greet',
        foo: 'bar',
        baz: 'quux'
    }, 
    type: 'POST',  
    dataType: 'json',
}).then(function (response) {
    console.log(response); // DEBUG
    if (response.error) {
        alert('Greet Error: ' + response.error);
    } else {
        alert(response.greet);
    }
}).catch(function (jqXHR) {
    console.log('AJAX Error', jqXHR); // DEBUG
    alert('AJAX Error: Request failed');
});

PHP:

<?php
$input = $_POST;
$response = array();

if (!isset($input['action'])) {
    $response['error'] = 'Action parameter required';
} else {
    if ($input['action'] === 'greet') {
        if (!isset($input['foo']) || !isset($input['bar'])) {
            $response['error'] = 'Invalid greet request';
        } else {
            $response['greet'] = 'Welcome home, David!';
        }
    } else {
        $response['error'] = 'Unknown action';
    }
}

header('Content-Type: application/json; charset=utf8');
echo json_encode($response);