Hei, I am not going to discuss what is wpnonce and why you should use this in your plugin or how important to use this to secure your plugin
But here I am going to discuss how you can use wpnonce in ajax request, I mean if your plugin handles ajax request.
Steps that we need to follow are:

One: Create wpnonce value.
Two: Send wpnonce value as an extra parameter with ajax requestion
Three: Check ajax referrer with the wpnonce value that was created in step one and sent in step two.

Ok, how to create a wpnonce value ?
we need to use wordpress function wp_create_nonce() . See wordpress codex here.
< ?php $my_wpnonce= wp_create_nonce (‘you-look-nice’); ?> // “you-look-nice” is just a string, u can use whatever u want. here $my_wpnonce will get a hash from wp_create_nonce. Oh that is not direct hash of “you-look-nice” but based on user id, time and that string. To know more about this function please check pluggable.php in wp-includes folder

Now send wpnonce value $my_wpnonce as an extra parameter while seding ajax req.

Now to process the ajax request in your script at first u need to include the wp-config.php or how u handle this.. no problem. Just use this line after this to check the ajax referrer.

< ?php check_ajax_referer(“you-look-nice”); ?> /// “you-look-nice” ya same string that u used making wpnoce….
If the nonce value is not same then the hacker will be just got fucked!
note: check codex here for the function check_ajax_referer.

That’s it man.

Demo: pls see the ajax tab in sidebar in my blog. Hope people using theme like me will like this plugin/widget.

How to install: Just download the attached file, unzip and upload to plugins folder. Activate the plugin from plugins  list , Now add the widget from Design->widgets.

There are some setting to that u can set from Settings->Manchu Ajax Tab where you can set the width of tabs and container.

This is first stable release of this plugin/widget and I will add more features soon so that tabs are more flexibles and easily cusmizable from admin panel.

Plugin Name: ManchuAjaxTab
Description: Ajax tab plugin/widgets for wordpress sidebar
Version: 1.0
Author: Sabuj Kundu aka manchumahara
Tabs: Recent Posts, Recent Comments, Tag clouds, Blogroll, Archives and Categories. More are comming soon with more features
License: GPL2
Note: No ajax or js library is used here. I mean raw ajax/js code is used to make it simple and faster loading.
Download: Note: There is a file embedded within this post, please visit this post to download the file.

Change log v1.1(2nd release 02.11.08):

• Admin interface to give custom name for tabs. This will be help full to use local language. Though this is not fully supported for localization. Hope I will give this support in next release.
• Custom width for tab ‘div’ and container or result ‘div’. This will help to maintain sidebar width and theme design using div based concept.
• Fix for custom or SEO friend URL.

Don’t forget to make comment if this is help full for you or not. Hope I will add more features on it soon. So keep eye on my blog regularly.

Thanks

http://www.alexajax.com/randomphotos  with CI –Xajax a