timeago.js

/*
 * JavaScript Pretty Date
 * Copyright (c) 2008 John Resig (jquery.com)
 * Licensed under the MIT license.
 */

// Takes an ISO time and returns a string representing how
// long ago the date represents.
TimeInWordsHelper = {
  distanceInWords: function(time) {
    var date = time,
		diff = (((new Date()).getTime() - date.getTime()) / 1000),
		day_diff = Math.floor(diff / 86400);

	if ( isNaN(day_diff) || day_diff < 0)
		return;
		
	return day_diff == 0 && (
			diff < 60 && Math.floor( diff ) + " segundos" ||
			diff < 120 && "1 minuto" ||
			diff < 3600 && Math.floor( diff / 60 ) + " minutos" ||
			diff < 7200 && "1 hora" ||
			diff < 86400 && Math.floor( diff / 3600 ) + " horas") ||
		day_diff == 1 && "1 dia" ||
		day_diff < 7 && day_diff + " dias" ||
		day_diff < 14 && "1 semana" ||
		day_diff < 31 && Math.ceil( day_diff / 7 ) + " semanas" ||
		day_diff < 355 && Math.ceil( day_diff / 31 ) + " meses" ||
		day_diff > 356 && "Muito tempo";
  },
  convertBySelector: function(el, selector) {
    var now = new Date()
 	// implementei um class selector simples para evitar bloat do jquery (codigo desnecessario) no widgets
	var els = document.getElementsByTagName(el);
	for (var i=0; i < els.length; i++) {
		if (els[i].getAttribute('class') == selector) {
			var oldInner = els[i].innerHTML;
			var title = els[i].getAttribute('title');
			if (title.length > 10) {
				var date = new Date(title);
			} else {
				var date = new Date(title*1000);
				els[i].setAttribute('title', date);
			}
			els[i].innerHTML = TimeInWordsHelper.distanceInWords(date) + ' atr&#225;s'
		}
	}
  }
};
try {
	TimeInWordsHelper.convertBySelector('span', 'gmttime');
} catch(e){}
setInterval(function() {
	TimeInWordsHelper.convertBySelector('span', 'gmttime');
}, 1000);