1. A non-transitory computer-readable medium embodying a program that, when executed in at least one computing device, causes the at least one computing device to at least: determine a plurality of behavior elements of a code library that are compatible with a data element of a document object model according to respective data contracts associated with individual ones of the plurality of behavior elements, the respective data contracts identifying which input data is valid for the individual ones of the plurality of behavior elements, the individual ones of the plurality of behavior elements configured to consume at least one data element as input data and produce a user interface feature; select a particular behavior element of the plurality of behavior elements according to a plurality of rules, the plurality of rules specifying at least one of: a compatibility between two or more of the plurality of behavior elements and a compatibility between at least one of the plurality of behavior elements and at least one data element; generate a mapping of the selected particular behavior element to the data element; and apply the selected particular behavior element to the data element.