International Journal of Modern Engineering Research (IJMER)
Online databases, also called web databases, comprise the deep web tag and value. Compared with WebPages in the surface web, which can be accessed by using a unique URL, pages in the deep web are dynamically generated in response to a user query submitted through the query interface of a web database. Upon receiving a user's query, a web database returns the relevant data, either structured or semi structured, encoded in the HTML pages. Many web applications, such as data integration, met querying and comparison shopping, need the data from multiple web databases. For these applications to further utilize the data embedded in HTML pages, the automatic data extraction is necessary.