A server receives a hypertext request from a client. The server looks up a hypertext document, wherein looking up comprises obtaining a first HTML element and a second HTML element and combining the first HTML element and second HTML element into a hypertext document, in response receiving the hypertext request from the client. The server parses the hypertext document for timeliness tags. The server generates at least one header tag based on the timeliness tags. The server determines whether at least one expired tag is among the timeliness tags. Responsive to a determination that at least one expired tag is among the timeliness tags, the server can look up a timeliness tag rule corresponding to the at least one timeliness tag.