We develop a semantics based approach to process information on the semantic web. We show how Horn logic can be used to denotationally capture the semantics of mark-up languages designed for describing resources on the semantic web (such as RDF). The same approach can also be used to specify the semantics of query languages for the semantic web. The semantics of both the resource description languages and the query languages are executable and when put together can be used to compute answers to semantic web queries. The main advantage of this semantic-based approach to processing the semantic web is that these executable semantics can be developed extremely quickly. Thus, as the semantic web mark-up languages evolve rapidly, their implementations can be developed at the same pace. In this paper, we present our approach based on denotational semantics and Horn logic. Our approach is quite general, and applicable to any description format (XML, RDF, DAML, etc.), though in this paper we illustrate it via RDF (Resource Description Framework).