What is "noscript"

NoScript (or NoScript Security Suite) is a free and open-source extension for Mozilla Firefox, SeaMonkey, and other Mozilla-based web browsers, created and actively maintained by Giorgio Maone, an Italian software developer and member of the Mozilla Security Group. NoScript allows executable web content such as JavaScript, Java, Flash, Silverlight, and other plugins only if the site hosting is considered trusted by its user and has been previously added to a whitelist. NoScript also offers specific countermeasures against security exploits.