Why doesn't javascript work in php?

Question

PHP

Added insert header and footer to all pages, js stopped working. The code is executed, it is visible in the console, but the page seems to be frozen.

<?php
require "blocks/header.php";
 ?>

    <div class="container prices">
      <br>
      <p>
    <button style="margin-right: 20px; "id="btn" type="button" class="btn btn-primary active btn-lg">Шугаринг</button>
    <button id="btn" type="button" class="btn btn-default btn-lg">Массаж</button>
      </p>
      <br>
      <!-- СТОИМОСТЬ УСЛУГ ШУГАРИНГА -->
      <table class="table table-bordered">
        <thead>
 
        </tbody>
      </table>
      <!-- СТОИМОСТЬ УСЛУГ МАССАЖА -->
      <table class="btn-service table table-bordered">
        <thead>
          <tr>
          <th>УСЛУГА</th>
          <th>СТОИМОСТЬ</th>
          <th>ВРЕМЯ</th>
        </tr>
        </thead>
        <tbody>
 
        </tbody>
      </table>
    </div>
    <br>

    <?php
    require "blocks/footer.php";
    echo "<script type="text/javascript" src="js/javascript.js"></script>";
     ?>

<div id="footer">
  <div class="container">
    <div class="row centered">
    <a href="#"><i class="fa fa-whatsapp"></i></a>
    <a href="#"><i class="fa fa-instagram"></i></a>
    <a href="#"><i class="fa fa-vk"></i></a>
    </div>
  </div>
</div>
    <script type="text/javascript" src="js/javascript.js"></script>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
    <script src="js/bootstrap.min.js"></script>
    <script src="js/npm.js"></script>
  </body>
</html>

var btn1 = document.getElementsByClassName('btn');
var table1 = document.getElementsByClassName('table');
console.log(btn1);
for (var i = 0; i < btn1.length; i++) {
  btn1[1].addEventListener('click', function(){
      if (btn1[1]) {
        for (var i = 0; i < table1.length; i++) {
          table1[i].classList.add('btn-service');
          btn1[i].classList.remove('btn-default', 'btn-primary', 'active');
        }
        table1[1].classList.remove('btn-service');
        btn1[1].classList.add('btn-primary', 'active');
      }
      });
      btn1[0].addEventListener('click', function(){
      if (btn1[0]) {
        for (var i = 0; i < table1.length; i++) {
          table1[i].classList.add('btn-service');
          btn1[i].classList.remove('btn-default', 'btn-primary', 'active');
        }
        table1[0].classList.remove('btn-service');
        btn1[0].classList.add('btn-primary', 'active');
      }
      });
}

Answer 1

Escape quotes

echo "<script type=\"text/javascript\" src=\"js/javascript.js\"></script>";