PHP if based on current system date - php

Question

Trying to setup a page that auto updates based on the users date/time.
Need to run a promotion for 2 weeks and each day it needs to change the displayed image.
Was reading through http://www.thetricky.net/php/Compare%20dates%20with%20PHP to get a better handle on php's time and date functions.Somewhat tricky to test, but I basically got stuck on:
<?php
$dateA = '2012-07-16';
$dateB = '2012-07-17';
if(date() = $dateA){
echo 'todays message';
}
else if(date() = $dateB){
echo 'tomorrows message';
}
?>
I know the above function is wrong as its setup, but I think it explains what I am aiming for.
Time is irrelevant, it needs to switch over at midnight so the date will change anyway.

Answer 1

You seem to need this:
<?php
$dateA = '2012-07-16';
$dateB = '2012-07-17';
if(date('Y-m-d') == $dateA){
echo 'todays message';
} else if(date('Y-m-d') == $dateB){
echo 'tomorrows message';
}
?>

Answer 2

you want
<?php
$today = date('Y-m-d')
if($today == $dateA) {
echo 'todays message';
} else if($today == $dateB) {
echo 'tomorrows message';
}
?>

Answer 3

I would go a step back and handle it via file names. Something like:
<img src=/path/to/your/images/img-YYYY-MM-DD.jpg alt="alternative text">
So your script would look something like this:
<img src=/path/to/your/images/img-<?php echo date('Y-m-d', time()); ?>.jpg alt="alternative text">

Answer 4

If you're going to do date calculations, I'd recommend using PHP's DateTime class:
$promotion_starts = "2012-07-16"; // When the promotion starts
// An array of images that you want to display, 0 = the first day, 1 = the second day
$images = array(
0 => 'img_1_start.png',
1 => 'the_second_image.jpg'
);
$tz = new DateTimeZone('America/New_York');
// The current date, without any time values
$now = new DateTime( "now", $tz);
$now->setTime( 0, 0, 0);
$start = new DateTime( $promotion_starts, $tz);
$interval = new DateInterval( 'P1D'); // 1 day interval
$period = new DatePeriod( $start, $interval, 14); // 2 weeks
foreach( $period as $i => $date) {
if( $date->diff( $now)->format("%d") == 0) {
echo "Today I should display a message for " . $date->format('Y-m-d') . " ($i)\n";
echo "I would have displayed: " . $images[$i] . "\n"; // echo <img> tag
break;
}
}
Given that the promotion starts on 07-16, this displays the following, since it is now the second day of the promotion:
Today I should display a message for 2012-07-17 (1)
I would have displayed: the_second_image.jpg