无法在隐藏/显示功能中传递目标ID

I have a "read more about supplier" displayed on each productarticle. When you click it, it's supposed to pop-up a small box with information about the supplier.

The code is working, but when you click the text it only toggles the productarticle on the top of the page. It looks like it can't seperate them and give them each a unique ID. I have no idea how to do this as I'm an amateur. Any help please?

HTML:

<div class="popup" onclick="myFunction1()" style="position:relative; left: 
70px;">Read more about <?php echo $supplier ?> here
 <span class="popuptext" id="myPopup">                                          
                   <b><?php $a = strtolower($supplier); if (strpos($a, 'supplier1') !== false) { echo 'Supplier 1 description'; } ?></b>                            
                   <b><?php $a = strtolower($supplier); if (strpos($a, 'supplier2') !== false) { echo 'Supplier 2 description'; } ?></b>                            
                   <b><?php $a = strtolower($supplier); if (strpos($a, 'supplier3') !== false) { echo 'Supplier 3 description'; } ?></b>
</span>
    </div>

js:

function myFunction1() {
var popup = document.getElementById("myPopup");
popup.classList.toggle("show");
}

the loop including all products:

<?php  $hr='';?>
<div class="row">
    <ul class="listProductItems clearfix">
        <?php  for ($art=0; $art<count($articles); $art++){ ?>
        <?php  $imagine     =$this->site_model->show_thumbs($articles[$art]['LA_ART_ID']); ?>
        <?php  $supplier        =(($articles[$art]['producer']!==NULL) ? $articles[$art]['producer'] : $articles[$art]['SUP_BRAND']); ?>
        <?php  //$criteria      =$this->site_model->article_criteria($articles[$art]['LA_ART_ID'],$articles[$art]['ga_id']); ?>
        <?php  $criteria        =$this->site_model->article_criteria_filter($articles[$art]['la_id']); ?>
        <?php  $criteria        .=$this->site_model->article_criteria($articles[$art]['LA_ART_ID'],$articles[$art]['ga_id']); ?>






        <?php  if ($hr !== $articles[$art]['generic_name'].' PRODUCED BY '.$supplier){ ?> 

            <div class="clearfix"></div>
            <?php  $hr = $articles[$art]['generic_name'].' PRODUCED BY '.$supplier; ?> 
        <?php  } ?>




        <li class="clearfix">
            <div class="span4" style="max-height:50px">
                <?php  if (isset($imagine)){ ?>

                <div class="thumbnail"><a href="<?php  echo site_url('type/'.$versiune.'/category/'.$tree.'/article/'.$articles[$art]['la_id']); ?>"><?php  echo $imagine; ?></a></div>
                <?php  } else { ?> 
                    <div class="thumbnail"><a href="<?php  echo site_url('type/'.$versiune.'/category/'.$tree.'/article/'.$articles[$art]['la_id']); ?>">