The ‘Same-origin Policy’ is introduced for security reasons.
It ensures that the content of our 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.
To avoid this same-origin policy, the proxy injection method is used. In the proxy injection mode, Selenium Server tricks the browser to be a real HTTP URL, i.e., it acts as a client-configured HTTP proxy, which sits between the browser and the application under test (AUT) and then masks the AUT under a fictional URL.