# Offline denominator filter

Open [index.html](index.html) locally in a browser. Check or uncheck Hatch, Ring and Solid; the page announces the **selected** pass count, denominator and percentage. “Include all” restores 25/48≈52.1%; “Hatch + Ring only” shows 23/36≈63.9%. The original source table remains visible, so a learner can see that filtering changes **scope**, not evidence. If no family is chosen, the interface explains that no denominator exists. It uses no external assets, network request, account, cookie, analytics, personal data or save operation.

Use [the paper denominator mat](../print/denominator-mat.pdf) and its [full text/tactile alternative](../print/TEXT-ALTERNATIVES.md) for the same calculation. Keyboard checkboxes and buttons have native focus behaviour, visible outlines and an announced status. Browser accessibility still needs actual assistive-technology/user trial; this is a desk-checked implementation. The fictional register never establishes public accessibility or safety. All JavaScript is original [Apache 2.0](../CODE-LICENSE.txt).