php - How to display the read more and read less button in WordPress

I am getting the list from the database and now I have to add the read more and read less button depending upon the content but I am not getting it. I am not getting any error in the console.

if($loop->have_posts() ) {
while($loop->have_posts() ) {
    $loop->the_post();
    $tid = $loop->ID;

 $data .='<li>
        
        <div class="overflowSet"><div class="imgwrap" style="background-image:url('.get_the_post_thumbnail_url($tid).')"></div></div>
        <h5>'.wp_trim_words(get_the_title($tid),9, '...').'</h5>
        <p class="countcontent">'.$the_content.'</p>
    </li>';


    }
}
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I added the below script to display the read more and less

$data .='<script>
jQuery(function($){
var maxLength = 390;
var moretxt = "...Read More";
var lesstxt = "Read Less";

$(".countcontent").each(function($) {
    var myStr = $(this).text();
    if (jQuery.trim(myStr).length > maxLength) {
      var newStr = myStr.substring(0, maxLength);
      var removedStr = myStr.substring(maxLength, $.trim(myStr).length);
      $(this).empty().html(newStr);
      $(this).append(\'<span class="more-text">' + removedStr + '</span>\');
      $(this).append(\'<a href="javascript:void(0);" class="read-more more">' + moretxt + '</a>\');

    }
  });

  $(".read-more").click(function() {
    if($(this).hasClass("more")){
        $(this).removeClass("more");
        $(this).text(lesstxt);
        $(this).siblings(".more-text").show();
    }
    else {
        $(this).addClass("more");
        $(this).text(moretxt);
        $(this).siblings(".more-text").hide();
    }

  });

 });

   </script>';
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I am getting the issue in this code

 jQuery(this).append(\'<span class="more-text">' + removedStr + '</span>\');
  jQuery(this).append(\'<a href="javascript:void(0);" class="read-more more">' + moretxt + '</a>\');
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If I add the below code then I am getting the text.

 jQuery(this).append(\'<span class="more-text">Read less</span>\');
  jQuery(this).append(\'<a href="javascript:void(0);" class="read-more more">Read more</a>\');
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