The “Same Origin Policy” is an essential theory in web application and introduced for security reason, It ensures that scripts contained in a first web page to access data in a second web page, but only if both web pages have the same origin. Means content of your site will never be accessible by a script from another site. As per the policy, any code loaded within the browser can only operate within that website’s domain.
Why is it important?
Techniques for relaxing Same Origin Policy:
In some case, Same Origin Policy is too restrictive, the posing problem for large websites that use multiple subdomains. Some techniques for relaxing it: