We can also make JSON POST request using the jQuery.post() function. If you want to use GET request. please refer to the previous post.
jQuery & JSON – Make JSON GET request using jQuery.getJSON()

 
Update @ 2011-10-13: This example does not work for Cross Domain POST request since the Current jQuery version(1.6.4) does not allow a Cross Domain POST request. For more information, you can refer to Mark Needham – jQuery: $.post, ‘jsonp’ and cross-domain requests

So if you want to make a Cross Domain GET request. Take a look on the following post.
jQuery & JSON – Make Cross Domain Request Using jQuery.getJSON() with JSONP

 
Here is the new server.php Continue reading jQuery & JSON – Make JSON POST request using jQuery.post() →