facebook_relative_time.func.php

<?php
/* Notes:
   - This is part of a much bigger "core" class for a website.
   - ->make_time($unix_timestamp,$data_parameters) is pretty much date() but using the logged in user's timezone
*/


        function fb_reltime($time,$html = true) // assumes a date in the past
        {
                if($time > TIME)
                        { $future = 1; } else { $future = 0; }

                $seconds = TIME - $time;
                if($seconds < 5)
                {
                        $reltime = "just now";
                }
                else if($seconds < 60) // Less than a Minute
                {
                        if($seconds == 1) { $reltime = "{$seconds} second ago"; }
                        else { $reltime = "{$seconds} seconds ago"; }
                }
                else if($seconds <= 60*60) // Less than an Hour
                {
                        $minutes = floor($seconds / 60);
                        if($minutes == 1) { $reltime = "{$minutes} minute ago"; }
                        else { $reltime = "{$minutes} minutes ago"; }
                }
                else if($this->make_time($time,"Y") < $this->make_time(TIME,"Y")) // More than a Year Ago
                {
                        $reltime = $this->make_time($time,"F j, Y \a\\t g:ia");
                }
                else if((($this->make_time($time,"N") == ($this->make_time(TIME,"N")-1)) || ($this->make_time($time,"N") == 7 && $this->make_time(TIME,"N") == 1)) && $seconds < 60*60*48) // Yesterday
                {
                        $reltime = "Yesterday at ".$this->make_time($time,"g:ia");
                }
                else if($seconds <= 60*60*24) // Less than a Day
                {
                        $hours = floor(($seconds / 60) / 60);
                        if(($seconds / 60) / 60 < 1.5) { $reltime = "about an hour ago"; }
                        elseif($hours < 2) { $reltime = "over an hour ago"; }
                        else { $reltime = "{$hours} hours ago"; }
                }
                else if($seconds < 60*60*24*4) // Less than Four Days Ago
                {
                        $reltime = $this->make_time($time,"D \a\\t g:ia");
                }
                else
                {
                        $reltime = $this->make_time($time,"F j \a\\t g:ia"); // Four+ Days Ago, but Less than a Year Ago
                }
                if(!$html) { return $reltime; }

                return '<abbr title="'.$this->make_time($time,"D, d M Y H:i:s O").'" data-epoch="'.$time.'" class="js-update-time">'.$reltime.'</abbr>';

        }

facebook_relative_time.js

function fb_reltime(seconds,html)
{
	if(!html) { var html = false; }
	var now_date = new Date();
	var TIME = Math.floor((new Date()).getTime() / 1000);
	//var seconds = Math.floor(time_ms / 1000);
	var time_ms = seconds * 1000;
	var date = new Date(time_ms);
	var reltime;
	seconds = TIME - seconds;

	var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];
	var sdays= ["Sun","Mon","Tue","Wed","Thu","Fri","Sat"];
	var months = ["January","February","March","April","May","June","July","August","September","October","November","December"];

	if(seconds < 5) // Five or Less Seconds Ago
	{
		reltime = "just now";
	}
	else if(seconds < 60) // Less than a Minute Ago
	{
		reltime = seconds + " seconds ago";
	}
	else if(seconds <= 60*60) // Less than an Hour Ago
	{
		var minutes = Math.floor(seconds / 60);
		if(minutes == 1) { reltime = "1 minute ago"; }
		else { reltime = minutes + " minutes ago"; }
	}
	else if(date.getFullYear() < now_date.getFullYear()) // Over a Year Ago
	{
		var thr = tfhr_to_thr(date.getHours());
		reltime = months[date.getMonth()] + " " + date.getDate() + ", " + date.getFullYear() + " at " + thr[0] + ":" + ddigit(date.getMinutes()) + thr[1];
	}
	else if(((date.getDay() == now_date.getDay() - 1) || (date.getDay() == 6 && now_date.getDay() == 0)) && (seconds < 60*60*48)) // Yesterday
	{
		var thr = tfhr_to_thr(date.getHours());
		reltime = "Yesterday at " + thr[0] + ":" + ddigit(date.getMinutes()) + thr[1];
	}
	else if(seconds <= 60*60*24) // Less than a Day Ago
	{
		var hours = Math.floor((seconds / 60) / 60);
		if((seconds / 60) / 60 < 1.5) { reltime = "about an hour ago"; }
		else if(hours < 2) { reltime = "over an hour ago"; }
		else { reltime = hours + " hours ago"; }
	}
	else if(seconds < 60*60*24*4) // Less than Four Days Ago
	{
		var thr = tfhr_to_thr(date.getHours());
		reltime = sdays[date.getDay()] + " at " + thr[0] + ":" + ddigit(date.getMinutes()) + thr[1];
	}
	else // Four+ Days Ago
	{
		var thr = tfhr_to_thr(date.getHours());
		reltime = months[date.getMonth()] + " " + date.getDate() + " at " + thr[0] + ":" + ddigit(date.getMinutes()) + thr[1];
	}
	if(html)
	{
		return '<abbr title="' + sdays[date.getDay()] + ', ' + date.getDate() + " " + months[date.getMonth()] + " " + date.getFullYear() + ' ' + ddigit(date.getHours()) + ":" + ddigit(date.getMinutes()) + ":" + ddigit(date.getSeconds()) + ' ' + gettz(date) + '" data-epoch="' + Math.floor(date.getTime() / 1000) + '" class="js-update-time">' + reltime + '</abbr>';
	}
	return reltime;
}
function tfhr_to_thr(hours)
{
	var ampm;
	var valreturn;
	if(hours < 24 && hours > 11) { ampm = "pm"; }
	else if(hours < 12 || hours == 24) { ampm = "am"; }

	if(hours == 0) { returnval = "12"; }
	else if(hours > 12) { returnval = hours - 12; }
	else { returnval = hours; }

	return [returnval,ampm];
}
function ddigit(int)
{
	if(int < 10) { return "0" + int; } else { return int; }
}
function gettz(date)
{
	var offset = date.getTimezoneOffset();
	var str;
	if(offset < 1) { str = "+"; } else { str = "-"; }
	str = str + ddigit(Math.floor(offset / 60));
	str = str + ddigit(offset % 60);
	return str;
}
function update_time()
{
	for(var i = 0; i < document.getElementsByClassName("js-update-time").length; i++)
	{
		document.getElementsByClassName("js-update-time")[i].innerHTML = fb_reltime(document.getElementsByClassName("js-update-time")[i].getAttribute("data-epoch"));
	}
}