Web Documents Structures as Source for Machine-Understandable Document

The web documents are not understandable by computers. And, web documents cross the web hold nourmance amount of information. To gain the maximum precision of reaching precise results, understanding these web documents is vital task. Moreover, it has always been the case that the Semantic Web is an extension of the current web. The Semantic Web or Web 3.0 is a collection of components that work together so that a machine is able to process and understand information. In order for this vision to be realized, formal standards for representing and interpreting data must be formulated and imposed. These formal standards include machine understandable ontologies Ontology Web Language (OWL). The Semantic Web vision provides the current Web with necessary infrastructure that allows computer to process knowledge and one of the cornerstones of this infrastructure is the Ontology. As this survey focuses on "web documents" as source for machine-understable document, we will discuss it in details how the researchers dealt with these web documents in order to build ontology.