Besides elevating privacy concerns, HTML5 also adds a few tools to enhance user privacy. A mechanism is defined whereby user agents can share blacklists of domains that should not be allowed to access web storage. Content Security Policy is a proposed standard whereby sites may assign privileges to different domains, enforcing harsh limitations on JavaScript use to mitigate cross-site scripting attacks. HTML5 also adds HTML templating and a standard HTML parser which replaces the various parsers of web browser vendors. These new features formalize previously inconsistent implementations, reducing the number of vulnerabilities though not eliminating them entirely.