US Patent 9342617 Unique identifiers for browsers

A webpage may be downloaded by a browser at a computing device. Such downloaded webpage may be associated with a reference to a browser identifier file. The browser may be directed to access the referenced browser identifier file. As a result, the browser may automatically check a local browser cache for the referenced browser identifier file. A request regarding the referenced browser identifier file may be sent over a communication network to an identifier server. Such request may be indicative of whether the referenced browser identifier file is found in the local browser cache. A response may be received from the identifier server. Such response may include the referenced browser identifier file when the referenced browser identifier file (or a current version thereof) is not found in the local browser cache. Alternatively, the response may include an indicator when the referenced browser identifier file is found in the local browser cache. The contents of the referenced browser identifier file may be made available to the browser and other related applications.