Accessibility overlays: why painting over problems doesn't fix them

There's a category of product that promises to make any website accessible by adding a single line of JavaScript. A floating widget appears in the corner, offering controls for contrast, font size, reading guides, and color adjustments. Some even claim compliance with WCAG, the EAA, or the ADA. The pitch is appealing: paste a script tag, get a toolbar, check the compliance box. No code changes, no design work, no developer time. It sounds too good because it is. What overlays actually do These widgets typically inject CSS and JavaScript that modifies how a page looks and behaves on the client side. Common features include: Font size and spacing controls that adjust text display properties Contrast modes that swap color palettes to higher-contrast themes Reading aids like a line guide that follows the cursor, link highlighting, and title emphasis Animation controls for pausing motion on the page Profile presets ("seizure-safe", "ADHD-friendly", "vision-impaired") that bundle several adj