Web services are becoming the dominant way to provide access to on-line information. Web services have a lot of applications, like e-mail, web search engine, auction network and internet banking. On the web services, web application technology and dynamic webpage technology are very important, but hackers take advantage of web application vulnerabilities and dynamic webpage technology to inject malicious codes into webpages. However, a part of the web sites have neglected the issue of security. In this paper, we propose a novel approach for detecting malicious webpages by URL features, anomaly semantics, potential dangerous tags and tag attributes. This research proposed approach mainly consists of three parts: (1) scripting language and automatic link filter. (2) malicious feature. (3) scoring mechanism. By first part, this step can filter out normal webpages to increae detection speed. Second part can identify some known malicious attacks. Third part can search some unknown malicious webpages by scoring. Our experimental results show that the proposed approach achieves low false positive rate and low false negative rate.