The <noscript> tag no longer works reliably. Script blockers and other tools may disable or hide them, or even change them into <span> elements and whatnot. Therefore, you better use the aproach shown here.
When the .noscript elements are removed from within a body.onload handler, the .noscript elements will be visible until the whole page has been loaded. Directly embedding some JS after the elements in question will remove them, while the page is still being parsed (aka immediately).
Check the source code of this page.