how to check the length of the php array in javascript

Question

I have two div 1st div contains some value and second div has the
php array which is fetching from the backend. i want to check on page load that if the array is empty or it contains some value using the javascript. if it contains the value i should minimize the 1st div else it should expand. code:

<div class="firstdiv ">
  <div >
    <p class="jb_text"><?php echo $per->name;?></p><hr>
  </div>
</div>

<div class="seconddiv ">
    <div class="panel-group" >
      <?php if($data): ?>
        <?php foreach($data as $work): ?>
          <div class="panel panel-default" id = "transp">
           <div class="col-lg-2 col-md-2 col-sm-2 col-xs-2 cd-name text-capitalize"><?php echo $work->first_name." ".$work->last_name; ?>
           </div>   
          </div> 
        <?php endforeach; ?>
      <?php endif; ?>
    </div>
</div>

how to check the length of the php array in javascript.

Answer 1

You can't "count the php array with javascript". Php is server side, javascript is client side. That being said, you can count the displayed element by the php foreach .

To do so, with Jquery you can go with :

if(!$('.panel panel-default').length) {
    $('.seconddiv').hide();
}

Answer 2

in browser you need to count the div or element by class in this case

<script>
seconddivLength = document.querySelectorAll(".panel.panel-default").length;
alert("seconddiv Length is: " + seconddivLength)
</script>

Answer 3

You can't count a PHP array with Javascript.

Try something like this though.

   <div class="firstdiv ">
      <div >
        <p class="jb_text"><?php echo $per->name;?></p><hr>
      </div>
    </div>

    <div class="seconddiv ">
        <div class="panel-group" >
          <?php if(isset($data) && is_array($data) && count($data) >= 1): ?>
            <?php foreach($data as $work): ?>
              <div class="panel panel-default" id = "transp">
               <div class="col-lg-2 col-md-2 col-sm-2 col-xs-2 cd-name text- 
   capitalize"><?php echo $work->first_name." ".$work->last_name; ?>
               </div>   
              </div> 
            <?php endforeach; ?>
          <?php else: ?>
            <!-- What ever else you want if its empty -->
          <?php endif; ?>
        </div>
    </div>