Tools and techniques are provided to assist in gathering web analytics data from wireless devices and in other configurations where passing data to an analytics server in a web-beacon query string has been difficult due to lack of an embedded scripting language and/or inaccessibility of desired data values. A dynamic variable specification is built on the web-reading device, including variables with associated data sources, operators, and literal values. The dynamic variable specification is sent to an analytics server, where an interpreter gathers data values and assigns them to variables.