Cross Site Scripting (XSS) vulnerabilities are among the top risks to web application security. However many web application developers have only a vague idea of what XSS is, let alone how to test for it or protect against it. Many web application frameworks such as Struts or Tapestry have some controls for preventing XSS attacks. Yet I’ve seen developers disable framework protections resulting in vulnerable applications. Usually this is simply due to ignorance or lack of attention. A basic awareness of what web frameworks do to prevent XSS vulnerabilities is required to stop developers making dumb, though potentially serious mistakes.