JS/CSS Scroll to top

I have these simple tabs on my website but im missing a feature:

Im reading a tab and scrolling to the bottom

When im done with reading the tab and switching to another tab, the scroll position stays the same.

What im trying to achieve is, automatically scroll to the top whenever a tab is clicked.
(Not to the top of the whole page, just scroll to the top of the tab content.)

Also, is there a way to display the ‘scroll to top’ function in a smooth transition / animation?

Tried to explain as understandable as possible, if something is unclear please let me know

Glad for any help, much appreciated

const btn = [].slice.call(document.getElementsByTagName('button'))
btn.forEach((item, index) => {
  item.addEventListener('click',function(){
    btn.forEach((item) => {item.classList.remove('active')})
    item.classList.add('active')
    document.getElementById('tab').setAttribute('data-tab', index)
  })
}  
)


// When the user scrolls the page, execute myFunction
window.onscroll = function() {myFunction()};

// Get the header
var header = document.getElementById("myHeader");

// Get the offset position of the navbar
var sticky = header.offsetTop;

// Add the sticky class to the header when you reach its scroll position. Remove "sticky" when you leave the scroll position
function myFunction() {
  if (window.pageYOffset > sticky) {
    header.classList.add("sticky");
  } else {
    header.classList.remove("sticky");
  }
}
button {background-color:#000;color:#fff}


.wrapper {
    overflow: hidden;
}

.tabs {
    position: relative;
    -webkit-transition: all .9s ease-in-out; 
    -moz-transition: all .9s ease-in-out; 
    -ms-transition: all .9s ease-in-out; 
    -o-transition: all .9s ease-in-out; 
    transition: all .9s ease-in-out;
    pointer-events:none;
 
}

.tabs> * {
    width: 100%;
}

.tabs[data-tab='1'] {
    transform: translateX(-100%);
}

.tabs[data-tab='2'] {
    transform: translateX(-200%);
}
.tabs[data-tab='3'] {
    transform: translateX(-300%);
}
.tabs[data-tab='4'] {
    transform: translateX(-400%);
}

.inliner {

    white-space: nowrap;
}

.inliner > * {
    display: inline-block;
    *display: inline;
    *zoom: 1;
    font-size: 1rem;
    letter-spacing: normal;
    vertical-align: top;
    word-spacing: normal;
    white-space: normal;
}

.sticky {
  position: fixed;
  top: 0;
  width: 100%
}



.textabove {
  font-size:40px;
   margin-bottom:40px}
<div class="textabove">Some content above the tabs</div>
<div class="wrapper">
 <div id="myHeader"> 
      <button> Tab 1</button>
       <button> Tab 2</button>
       <button> Tab 3</button>
  </div>        
    <div id="tab" class="tabs inliner">
        <div>
            <h2>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</h2>
        
        </div>
        <div>
            <h2>Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.</h2>
       
        </div>
        <div>
            <h2>Content 3</h2>
            
        </div>
    </div>
</div>