html_Menu

<div id="London" class="tabcontent">
  <h3>London</h3>
  <p>London is the capital city of England.</p>
</div>

<div id="Paris" class="tabcontent">
  <h3>Paris</h3>
  <p>Paris is the capital of France.</p>
</div>

<div id="Tokyo" class="tabcontent">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>

<div id="Oslo" class="tabcontent">
  <h3>Oslo</h3>
  <p>Oslo is the capital of Norway.</p>
</div>

<button class="tablink" onclick="openCity('London', this, 'red')" id="defaultOpen">London</button>
<button class="tablink" onclick="openCity('Paris', this, 'green')">Paris</button>
<button class="tablink" onclick="openCity('Tokyo', this, 'blue')">Tokyo</button>
<button class="tablink" onclick="openCity('Oslo', this, 'orange')">Oslo</button>