The <noscript> tag has an alternative content, which is displayed in the browsers, that don’t support scripts, or the browsers, where the script support is disabled by the user. In other cases, the browser ignores this tag and its content.
In HTML5 the <noscript> tag can be placed in the <head> and <body> elements. In HTML4 it can be used only in the <body> element. If the <noscript> is placed in the <head> tag, it must contain only the <link>, <style> and <meta> tags.
The <noscript> tag comes in pairs; the closing tag is required.