ago.js

function ago(v, f) {
    v = ~~((Date.now() - v)/1e3);
    var a, b = { second: 60, minute: 60, hour: 24, day: 7, week: 4.35,
        month: 12, year: 1e4 }, c;
 
    for (a in b) {
        c=v % b[a];
        if (!(v = (f||parseInt)(v / b[a])))
            return c + ' ' + (c-1 ? a + 's' : a);
    }
}

// function ago(v,f){v=~~((Date.now()-v)/1e3);var a,b={second:60,minute:60,hour:24,day:7,week:4.35,month:12,year:1e4},c;for(a in b){c=v%b[a];if(!(v=(f||parseInt)(v/b[a])))return c+' '+(c-1?a+'s':a)}}