Information Technology Journal1812-56381812-5646Asian Network for Scientific Information10.3923/itj.2012.408.413TanRuyue42012114Due to the explosive development of Internet technology, the web is becoming the world's largest database of information, effective management and utilization of web information is currently a hot issue. This study mainly discusses the extraction of web information. Traditional web information extraction is mainly based on DOM tree and HTML tag analysis. Based on VIPS, the study proposes visual block positioning algorithm for webpage information extraction through induction webpage visual features and visual block feature information. It inputs the theme-based webpages and BBS webpages for VIPS, analyzes the output of VIPS and the VBT and then defines visual characteristics such as text density and link text density. The study puts forward a visual block positioning algorithm VBPA. It will position the theme information block to one VBT node, then extract the theme information. Experimental results show that the visual block positioning algorithm based on visual features is superior to the traditional web information extraction algorithm and has a higher quality of information extraction.]]>Cai, D., S. Yu, J.R. Wen and W.Y. Ma,2003Proceedings of the 5th Asia Pacific Web Conference,2003pp: 406417Cai, D., S. Yu, J.R. Wen and W.Y. Ma,2003VIPS: A vision-based page segmentation algorithm.2003Liu, W. and X. Meng,2006Proceedings of the 9th SIGMOD International Workshop on Web and Databases,2006Chang, C.H., M. Kayed, R. Girgis and K.F. Shaalan,2006Inst. Electr. Electron. Eng. Trans. Knowledge Data Eng.,1814111428Sarawagi, S.,2002Proceedings of the 28th International Conference on Very Large Data Bases,2002Laender, A.H.F., B.A. Ribeiro-Neto, A.S. da Silva and J.S. Teixeira,2002ACM SIGMOD Record,318493Crescenzi, V. and G. Mecca,1998Inform. Syst.,23539565Saiiuguet, A. and F. Azavant,2001Data Knowledge Eng.,36283316