getActiveKey = function getActiveKey(keyName) {

        // Get key array for given name
        var keys = osk.keys[keyName];
        if (!keys)
            return null;

        // Find last matching key
        for (var i = keys.length - 1; i >= 0; i--) {

            // Get candidate key
            var candidate = keys[i];

            // If all required modifiers are pressed, use that key
            if (modifiersPressed(candidate.requires))
                return candidate;

        }

        // No valid key
        return null;

    }
Returns the single matching Key object associated with the key of the
given name, where that Key object's requirements (such as pressed
modifiers) are all currently satisfied.

@private
@param {String} keyName
    The name of the key to retrieve.

@returns {Guacamole.OnScreenKeyboard.Key}
    The Key object associated with the given name, where that object's
    requirements are all currently satisfied, or null if no such Key
    can be found.