jQuery plugin that makes individual radio-buttons focusable using the keyboard only. (Useful for accessibility, on a case-by-case basis.)

radioTabbable.jquery.js

$.fn.radioTabbable = function () {
    var groups = [];
    
    // group the inputs by name
    $(this).each(function () {
        var el = this;
        var thisGroup = groups[el.name] = (groups[el.name] || []);
        thisGroup.push(el);
    });

    $(this).on('keydown', function (e) {
        setTimeout(function () {
            var el = e.target;
            var thisGroup = groups[el.name] = (groups[el.name] || []);
            var indexOfTarget = thisGroup.indexOf(e.target);

            if (e.keyCode === 9) {
                if (indexOfTarget < (thisGroup.length - 1) && !(e.shiftKey)) {
                    thisGroup[indexOfTarget + 1].focus();
                }
                else if (indexOfTarget > 0 && e.shiftKey) {
                    thisGroup[indexOfTarget - 1].focus();
                }
            }
        });
    });
};