I assume you're talking about the <noscript> element (as opposed to something to do with the browser extension with a similar name)? In which case, it is defin

I assume you're talking about the <noscript> element (as opposed to something to do with the browser extension with a similar name)? In which case, it is definitely worth making websites as usable as possible without JavaScript. <noscript> is supported by pretty much all web browsers, including iOS Safari. Even if your website relies heavily on JavaScript, it is still a good idea to let non-JavaScript users know via a <noscript> element that JavaScript is required, instead of having the page look like a broken mess (or a blank screen). Do also keep in mind that search engines (generally) do not run JavaScript, so if you want page content to be indexed, it has to be present on the page as it is rendered without JavaScript. <noscript> may help achieve that.