test.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    
    <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
        <!-- chart.js library  -->
        <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>        
        <script src="https://npmcdn.com/Chart.Zoom.js@0.3.0/Chart.Zoom.min.js"></script>        
        <!-- <script defer src="js/testzoom.js"></script> -->
       
          
    <title>Document</title>
</head>
<body>
    <h1>test</h1>
<h1>test</h1>

<h1>test</h1>

<div style="max-width: 600px; max-height: 400px;" class="myChartDiv">
  <canvas id="myChart" width="600" height="400"></canvas>
</div>

<button id="reset_zoom">
  Reset zoom
</button>

<button id="disable_zoom">
  Disable zoom
</button>

<button id="enable_zoom">
  Enable zoom
</button>

<h1>test</h1>

<script defer src="js/testzoom.js"></script>

</body>


</html>