http://mdn.i2p/en-US/docs/Web/URI
URIs are commonly used as targets of HTTP requests, in which case the URI represents a location for a resource, such as a document, a photo, binary data. The most common type of URI is a Uniform Resource Locator ( URL ), which is known as the web address . URIs can be used to trigger behaviors other than fetching a resource, including opening an email client, sending text messages, or executing JavaScript, when used in other places such as the href of an HTML <a> link.