There are 3 ways to allow cross domain origin (excluding jsonp):
1) Set the header in the page directly using a templating language like PHP. Keep in mind there can be no HTML before your header or it will fail.
<?php header("Access-Control-Allow-Origin: http://example.com"); ?>
2) Modify the server configuration file (apache.conf) and add this line. Note that "*" represents allow all. Some systems might also need the credential set. In general allow all access is a security risk and should be avoided:
Header set Access-Control-Allow-Origin "*"
Header set Access-Control-Allow-Credentials true
3) To allow multiple domains on Apache web servers add the following to your config file
<IfModule mod_headers.c>
SetEnvIf Origin "http(s)?://(www\.)?(example.org|example.com)$" AccessControlAllowOrigin=$0$1
Header add Access-Control-Allow-Origin %{AccessControlAllowOrigin}e env=AccessControlAllowOrigin
Header set Access-Control-Allow-Credentials true
</IfModule>
4) For development use only hack your browser and allow unlimited CORS using the Chrome Allow-Control-Allow-Origin extension
5) Disable CORS in Chrome: Quit Chrome completely. Open a terminal and execute the following. Just be cautious you are disabling web security:
open -a Google\ Chrome --args --disable-web-security --user-data-dir