executes to transform a template representing the page into the actual page the instruction contains an identifier called a u201c resource identifier u201d that refers to the resource and all of its versions when the script is executed in response to a request to serve the page the resource retrieval instruction is passed to a resource versioning service together with the resource identifier the resource versioning service determines the version of the web site for which the page is being rendered called u201c the release to render u201d the release to render is typically either a live release that is currently being presented to customers or other consumers of the web site or a future release that is scheduled to be presented to customers at a future time the resource versioning service typically makes this determination based on the identity and current preferences of the user requesting the page discerned either by receiving this information along with the resource identifier from the template 39 s script or by accessing context information associated with the user and or the user 39 s web browsing session the resource versioning service uses the determined release to render together with the version of the release incorporated in the live release and changes earlier specified for the determined release to render and earlier scheduled releases to identify then retrieve or construct the appropriate version of the resource identified by the resource identifier the resource versioning service returns this version of the requested resource to the template 39 s script.