根据星期几更改背景图像

I am trying to change a div's background image based on the day of the week. The images are in a folder named 'img' I have the following code;

html

<?php
  $images_by_day = array('monday.jpg', 'tuesday.jpg', 'wednesday.jpg',  ...);
  $image_for_today = $images_by_day[date('w')];
?>

<div class="jumbotron indx-BG">
   //content
</div>

css (external style sheet)

.indx-BG {
  background: url('../img/<?php echo $image_for_today ?>.jpg') no-repeat center center;
 }

Its better you define seven different classes with different background images within the css file and then apply those classes within the elements using php file.

Like:

<div class="container <?php echo date('l')?>-bg" id="indx-jumbo">
   //content
</div>

And in your css file you define css classes like:

.monday-bg {
  background: url('../img/image_for_monday.jpg') no-repeat center center;
}
.tuesday-bg {
  background: url('../img/image_for_tuesday.jpg') no-repeat center center;
}
.
.
.
.sunday-bg {
  background: url('../img/image_for_sunday.jpg') no-repeat center center;
}

You shouldn't use PHP in a CSS file. A way to solve this problem is by adding the background-image inline, something like this:

<div class="container" id="indx-jumbo" style="background-image: url('../img/<?php echo $image_for_today ?>.jpg')">
   //content
</div>

You can't use PHP in css file. You can add background image inline. Please check following code.

<div class="container" id="indx-jumbo" style="background-image: url('../img/<?php echo date( "l", $timestamp); ?>.jpg')">
   //content
</div>

<?php
 $images_by_day = array('sunday.jpg','monday.jpg', 'tuesday.jpg',
                        'wednesday.jpg','thursday.jpg','friday.jpg','saturday.jpg');
 $image_for_today = $images_by_day[date('w')];
?>


<div class="container" id="indx-jumbo" 
style=" background: url('../img/<?php echo $image_for_today ?>') no-repeat center center;">
 //Content
</div>

Try to this.

<?php
  $images_by_day = array('monday.jpg', 'tuesday.jpg', 'wednesday.jpg', 'thursday.jpg','friday.jpg','saturday.jpg','sunday.jpg');
  $today = date('l');
  foreach ($images_by_day as $key => $value) {
    $day = substr($value,0,-4);
    $str = strcasecmp($day, $today);

    if($str == '0'){
        $background = $value;
    }
  }
?>

<div class="container" id="indx-jumbo" style="background-image: url('../img/<?= $background; ?>');">
   //content
</div>

You need to check if your image name contains day of a week. You can do it easily with php's substring inbuilt functions.

<?php
foreach($imagArray as $image)
{
    if(strpos($image,date('l'))
    {
       //display image and exit
    }

}

?>