Security on the web depends on a variety of mechanisms, including an underlying concept of trust known as the same-origin policy. This essentially states that if content from one site (such as "https://mybank.example1.com") is granted permission to access resources (like cookies etc.) on a web browser, then content from any URL with the same (1) URI scheme, (2) host name, "and" (3) port number will share these permissions. Content from URLs where any of these three attributes are different will have to be granted permissions separately.