js返回相对时间

//新浪微博

function relativeTime(dateString) {
    var values = dateString.split(" ");
    dateString = values[1] + " " + values[2] + ", " + values[5] + " " + values[3];
    var parsed_date = Date.parse(dateString);
    var relative_to = (arguments.length > 1) ? arguments[1] : new Date();
    var delta = parseInt((relative_to.getTime() - parsed_date) / 1000);
    delta = delta + (relative_to.getTimezoneOffset() * 60);

    if (delta < 60) {
        return 'just now';
    } else if (delta < 120) {
        return 'a minute ago';
    } else if (delta < (60 * 60)) {
        return (parseInt(delta / 60)).toString() + ' minutes ago';
    } else if (delta < (120 * 60)) {
        return 'about an hour ago';
    } else if (delta < (24 * 60 * 60)) {
        return 'about ' + (parseInt(delta / 3600)).toString() + ' hours ago';
    } else if (delta < (48 * 60 * 60)) {
        return '1 day ago';
    } else {
        return (parseInt(delta / 86400)).toString() + ' days ago';
    }
}

淡入淡出效果： http://www.cnblogs.com/rush/archive/2013/02/28/2937884.html