time.js

var minute = 1000 * 60;
var hour = minute * 60;
var day = hour * 24;
var halfamonth = day * 15;
var month = day * 30;

function getDateDiff(dateTimeStamp) {
    var now = new Date().getTime();
    var diffValue = now - dateTimeStamp;
    if (diffValue < 0) {
        return false;
    }
    var monthC = diffValue / month;
    var weekC = diffValue / (7 * day);
    var dayC = diffValue / day;
    var hourC = diffValue / hour;
    var minC = diffValue / minute;
    if (monthC >= 1) {
        result = "post at" + parseInt(monthC) + "month ago";
    } else if (weekC >= 1) {
        result = "post at" + parseInt(weekC) + "week ago";
    } else if (dayC >= 1) {
        result = "post at" + parseInt(dayC) + "day ago";
    } else if (hourC >= 1) {
        result = "post at" + parseInt(hourC) + "hour ago";
    } else if (minC >= 1) {
        result = "post at" + parseInt(minC) + "minute ago";
    } else
        result = "just now";
    return result;
}