<noscript> in <head>
If you didn’t know, it’s perfectly valid to use the <noscript> tag inside the “ element of a HTML page. And you’re allowed to include <link>, <style> or <meta> tags as its children.
I use this for my little focal length equivalent utility, by loading an additional stylesheet via a <link> tag: when a visitor has JavaScript disabled, it loads the style for the alternative <table> that’s also wrapped in a <noscript> element.