1. A computer program product comprising one or more computer-readable storage media having thereon computer-executable instructions that are structured such that, when interpreted by one or more processors of a computing system, cause the computing system to perform a method, the method comprising: an act of accessing code that contains information caused to be inserted by a code authoring entity, which information is structured in the code to be interpreted by a computing system to identify a target component of the code and input validation information to be applied to input of the target component; and an act of using the information to construct an input filter structured to be interpretable by a potential runtime environment as identifying the target component and the input validation information.