[PHP-WEBMASTER] having problem with sending information to php file using ajax

[Amin Gholian]

Hey,

I'm sending some parameters using Ajax code, but it never gets to my php file 
and never execute my php funtions. Here is my code:

var check = $.ajax({
                                type : "POST",
                                datatype : 'JSON',
                                url : "/library/ajax/ajax_functions.php",
                                data : {
                                                email : email,
                                                action : 'checkUsername'
                                },
                                success : function(msg) {
                                                _return(msg);
                                }
                });

I was wondering if you could help me out here, I'm using windows server 2012 
and IIS in order to run my php application.

Thank You,
Amin.