I need the text to change to a randomly generated when the button is clicked (A-Z, 0-9) (up to 15 symbols)

    <button class="genbtn" onclick="generate()"> Generate </button>
    <h2 class="gentext1" id="gentext1"></h2>
    <h2 class="gentext2" id="gentext2"></h2>
  </div>
</div>

</body>