http://ejohn.org/files/pretty.js

http://ejohn.org/files/pretty.js

function prettyDate(time){
 var date = new Date((time || "").replace(/-/g,"/").replace(/[TZ]/g," ")),
  diff = (((new Date()).getTime() - date.getTime()) / 1000),
  day_diff = Math.floor(diff / 86400);
   
 if ( isNaN(day_diff) || day_diff < 0 || day_diff >= 31 )
  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 < 7 && day_diff + " days ago" ||
  day_diff < 31 && Math.ceil( day_diff / 7 ) + " weeks ago";
}