Duplicate of:
What common web exploits should I know about?
This is a security question.
What should I
JavaScript injection is not at attack on your web application. JavaScript injection simply adds JavaScript code for the browser to execute. The only way JavaScript could harm your web application is if you have a blog posting or some other area in which user input is stored. This could be a problem because an attacker could inject their code and leave it there for other users to execute. This attack is known as Cross-Site Scripting. The worst scenario would be Cross-Site Forgery, which allows attackers to inject a statement that will steal a user's cookie and therefore give the attacker their session ID.