Ajax in Wordpress plugin - ajax

Question

I am creating a simple wordpress plugin and trying to use AJAX, but I always get 0 in ajax response.
<script type="text/javascript" >
jQuery(document).ready(function($) {
var data = {
action: 'my_action',
whatever: '1234'
};
jQuery.post("http://localhost/taichi/wp-admin/admin-ajax.php", data, function(response) {
alert(response);
});
});
</script>
<?php
add_action('wp_ajax_my_action', 'my_action_callback');
add_action( 'wp_ajax_nopriv_my_action', 'my_action_callback' );
function my_action_callback() {
echo "test";
die();
}
what am I doing wrong?

Answer 1

You have to put the add_action at the complete bottom of your file or else it won't find the callback function

Answer 2

Try to change :
jQuery.post("http://localhost/taichi/wp-admin/admin-ajax.php", data, function(response)
To :
jQuery.post(ajaxurl, data, function(response)
And check if it is working on the admin side first. It should work fine.

Answer 3

Error Return Values
If the AJAX request fails when the request url is wp-admin/admin-ajax.php, it will return either -1 or 0 depending on the reason it failed.
Read this
Edit
admin-ajax always return default '0' as output.so while you alerting response you will 0 only.using die() in callback function will terminate that.

Answer 4

Had the same problem, it turned out that my callback was inside a php file which was only included to my "Theme Options" page.
To check if the function is able to trigger trougth admin-ajax.php try to add var_dump(function_exists("your_callback_name")); to the bottom of the wp-admin/admin-ajax.php (before die( '0' );) and then have a look to your ajax output.

Answer 5

Try the following code in your plugin file. or in function.php
jQuery(document).ready(function($){
var ajaxURL = 'http://localhost/taichi/wp-admin/admin-ajax.php';
var dataString = 'action=mnd_news';
$.ajax({
type: "POST",
url: ajaxURL,
data: dataString,
cache: false,
success: function(response){
if(response != 'error') {
alert(response);
}
}
});
});
add_action('wp_ajax_mnd_news', 'get_mnd_ajax');
add_action( 'wp_ajax_nopriv_mnd_news', 'get_mnd_ajax' );
function get_mnd_ajax() {
echo "test";
die();
}