php countdown script - multiple countdowns per page

Question

I have the following php countdown script that counts down to a date and time. Please see the below example:

    <SCRIPT language="JavaScript" SRC="countdown.php?timezone=US/Pacific&countto=2011-06-25 00:00:00&do=t&data=Sorry, This Offer Has Expired."></SCRIPT>  

And countdown.php:

<?php
// we will be sending Javascript codes
header('Content-Type: text/javascript'); 

// select the timezone for your countdown
$timezone = trim($_GET['timezone']);
putenv("TZ=$timezone");

// Counting down to New Year's on 2020
$countdown_to = trim($_GET['countto']); // 24-Hour Format: YYYY-MM-DD HH:MM:SS"

// Getting the current time
$count_from = date("Y-m-d H:i:s"); // current time -- NO NEED TO CHANGE

// Date difference function. Will be using below
function datediff($interval, $datefrom, $dateto, $using_timestamps = false) {
  /*
$interval can be:
yyyy - Number of full years
q - Number of full quarters
m - Number of full months
y - Difference between day numbers
  (eg 1st Jan 2004 is "1", the first day. 2nd Feb 2003 is "33". The datediff is "-32".)
d - Number of full days
w - Number of full weekdays
ww - Number of full weeks
h - Number of full hours
n - Number of full minutes
s - Number of full seconds (default)
  */

  if (!$using_timestamps) {
    $datefrom = strtotime($datefrom, 0);
    $dateto = strtotime($dateto, 0);
  }
  $difference = $dateto - $datefrom; // Difference in seconds

  switch($interval) {

case 'yyyy': // Number of full years

  $years_difference = floor($difference / 31536000);
  if (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n",          $datefrom), date("j", $datefrom), date("Y", $datefrom)+$years_difference) > $dateto) {
    $years_difference--;
  }
  if (mktime(date("H", $dateto), date("i", $dateto), date("s", $dateto), date("n", $dateto), date("j", $dateto), date("Y", $dateto)-($years_difference+1)) > $datefrom) {
    $years_difference++;
  }
  $datediff = $years_difference;
  break;

case "q": // Number of full quarters

  $quarters_difference = floor($difference / 8035200);
  while (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom)+($quarters_difference*3), date("j", $dateto), date("Y", $datefrom)) < $dateto) {
    $months_difference++;
  }
  $quarters_difference--;
  $datediff = $quarters_difference;
  break;

case "m": // Number of full months

  $months_difference = floor($difference / 2678400);
  while (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom)+($months_difference), date("j", $dateto), date("Y", $datefrom)) < $dateto) {
    $months_difference++;
  }
  $months_difference--;
  $datediff = $months_difference;
  break;

case 'y': // Difference between day numbers

  $datediff = date("z", $dateto) - date("z", $datefrom);
  break;

case "d": // Number of full days

  $datediff = floor($difference / 86400);
  break;

case "w": // Number of full weekdays

  $days_difference = floor($difference / 86400);
  $weeks_difference = floor($days_difference / 7); // Complete weeks
  $first_day = date("w", $datefrom);
  $days_remainder = floor($days_difference % 7);
  $odd_days = $first_day + $days_remainder; // Do we have a Saturday or Sunday in the remainder?
  if ($odd_days > 7) { // Sunday
    $days_remainder--;
  }
  if ($odd_days > 6) { // Saturday
    $days_remainder--;
  }
  $datediff = ($weeks_difference * 5) + $days_remainder;
  break;

case "ww": // Number of full weeks

  $datediff = floor($difference / 604800);
  break;

case "h": // Number of full hours

  $datediff = floor($difference / 3600);
  break;

case "n": // Number of full minutes

  $datediff = floor($difference / 60);
  break;

default: // Number of full seconds (default)

  $datediff = $difference;
  break;
  }    

  return $datediff;
    }

// getting Date difference in SECONDS
$diff = datediff("s", $count_from, $countdown_to);
?>

// Heres where the Javascript starts
countdown = <?=$diff?>;

// Converting date difference from seconds to actual time
function convert_to_time(secs)
{
secs = parseInt(secs);  
hh = secs / 3600;   
hh = parseInt(hh);  
mmt = secs - (hh * 3600);   
mm = mmt / 60;  
mm = parseInt(mm);  
ss = mmt - (mm * 60);   

if (hh > 23)    
{   
   dd = hh / 24;    
   dd = parseInt(dd);   
   hh = hh - (dd * 24); 
} else { dd = 0; }  

if (ss < 10) { ss = "0"+ss; }   
if (mm < 10) { mm = "0"+mm; }   
if (hh < 10) { hh = "0"+hh; }   
if (dd == 0) { return (hh+":"+mm+":"+ss); } 
else {  
    if (dd > 1) { return (dd+" days "+hh+":"+mm+":"+ss); }
    else { return (dd+" day "+hh+":"+mm+":"+ss); }
}   
}

// Our function that will do the actual countdown
function do_cd()
{
if (countdown < 0)  
{   
    <?php
        if(strtolower(trim($_GET['do'])) == 'r' )
        {
    ?>
    // redirect web page
    document.location.href = "<?=$_GET['data']?>";
    <?php } ?>

    <?php
        if(strtolower(trim($_GET['do'])) == 't' )
        {
    ?>
    // change text
    document.getElementById('cd').innerHTML = "<?=$_GET['data']?>";
    <?php } ?>

}   
else    
{   
    document.getElementById('cd').innerHTML = convert_to_time(countdown);
    setTimeout('do_cd()', 1000);
}   
countdown = countdown - 1;  
}

document.write("<div id='cd'></div>\n");

do_cd();

<? exit(); ?>

can someone tell me how I can modify this script to allow it to be used in multiple places on one page. It does not work properly when you have more than on countdown per page.

Thanks in advance!

Answer 1

The PHP file is generating JavaScript that's targeting a specific ID:

document.getElementById('cd')

There should be only one ID on a page, so targeting more than one ID will break. You may want to switch to different IDs and multiple countdown.php files as a fast solution, or rewriting the PHP file so that it targets an ID that's passed in from the client side as a GET parameter.

That said, I'd strongly suggest ditching this entire solution. The PHP script doesn't sanitize or validate input. I could potentially run code on your web server by manipulating the GET string. It also seems to be unnecessary overhead — this can all be done on the client side.

Here's a jQuery countdown plugin that I think you should consider, and it does have timezone support.