This is actually specifically NOT want I want: "Modernizr does not add missing functionality to browsers; instead, it detects native availability of features a

This is actually specifically NOT want I want: "Modernizr does not add missing functionality to browsers; instead, it detects native availability of features and offers you a way to maintain a fine level of control over your site regardless of a browser’s capabilities." I understand that not all HTML5 features can be reproduced in JS, but for the ones that can (such as "placeholder"), I don't want to have to think about reimplementing it for older browsers when it could be done automatically.