app/templates/header.html

<div class="topnav" id="myTopnav">
  <a href="/" class="active">Home</a>
  <a href="/audio_to_text/">Speech to Text</a>
  <a href="javascript:void(0);" class="icon" onclick="myFunction()">
    <i class="fa fa-bars"></i>
  </a>
</div>



{% with messages = get_flashed_messages(with_categories=true) %}
{% if messages %}
  {% for category,message in messages %}

    <div class="alert">
        <span class="closebtn" onclick="this.parentElement.style.display='none';">&times;</span> 
        <strong>{{category}} :</strong> {{ message }}
    </div>
  {% endfor %}
{% endif %}
{% endwith %}