Описание тега noscript
NoneNoscript is an HTML element used to provide fallback content for scripts which fail to execute if the browser does not support the scripting language or if the user has disabled client-side scripting.
A noscript element should immediately follow the script element it is meant to replace.
noscript can also refer to a Firefox extension which selectively disables scripts.
NoScript blocks JavaScript, Java, Flash, Silverlight, and other "active" content by default in Firefox. This is based on the assumption that malicious websites can use these technologies in harmful ways. Users can allow active content to execute on trusted websites, by giving explicit permission, on a temporary or a more permanent basis. If "Temporarily allow" is selected, then scripts are enabled for that site until the browser session is closed.
[source: wikipedia]