1. A computer implemented method of responding to requests for content items of a web page, the method comprising, in a server computer, the steps of: receiving from a client computer a first request for a first content item of the web page, the first request being a request that is read by the server computer to be a request for a plurality of default content items of the web page; obtaining the plurality of default content items of the web page corresponding to the first request; responding to the first request with the plurality of default content items of the web page; receiving from the client computer a second request for a second content item of the web page, the second request being a request that is read by the server computer to be a request for a plurality of non-default content items of the web page; obtaining the plurality of non-default content items of the web page from the computer readable storage media of the server computer; and responding to the second request with the plurality of non-default content items of the web page, the plurality of non-default content items being cacheable in the client computer.