twitter_pretty_date.js

function prettyDate(time){
    var date = new Date((time || "")),
        diff = (((new Date()).getTime() - date.getTime()) / 1000),
        day_diff = Math.floor(diff / 86400);
    
    if (isNaN(date)){
        return '';
    }
    
    return day_diff == 0 && (
        diff < 60 && "just now" ||
        diff < 120 && "1 minute ago" ||
        diff < 3600 && Math.floor( diff / 60 ) + " minutes ago" ||
        diff < 7200 && "1 hour ago" ||
        diff < 86400 && Math.floor( diff / 3600 ) + " hours ago") ||
        day_diff == 1 && "Yesterday" ||
        day_diff < 14 && day_diff + " days ago" ||
        Math.ceil( day_diff / 7 ) + " weeks ago";
}