Mark all read time in JS

[Mike Mastrangelo]

I am using this API:
https://www.google.com/reader/api/0/mark-all-as-read

For the time stamp I was using: unreadCounts[i].newestItemTimestampUsec

However I want to support 1 day, 1 week, and 2 weeks:

            var time;

            var now = new Date(Date.now());

            if (timeFrame === AllReadTypes.day) {

                now.setDate(now.getDate() - 1);

                time = '' + now.getTime() * 1000;

            } else if (timeFrame === AllReadTypes.week) {

                now.setDate(now.getDate() - 7);

                time = '' + now.getTime() * 1000;

            } else if (timeFrame === AllReadTypes.weeks) {

                now.setDate(now.getDate() - 14);

                time = '' + now.getTime() * 1000;

            } else {

                time = unreadCounts[i].newestItemTimestampUsec;
            }

However I want to double check - is this the right time? Should I do something else?