Weird JS

HTML

<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<div class="high">
Test
</div>
<input type="button" onclick="expected();" value="Try the expected approach">
<input type="button" onclick="unexpected();" value="Try the unexpected approach">

CSS

.high{
  background-color:red;
}

JavaScript

function expected(){
    var check= document.getElementsByClassName("high");
    for(var k = 0; k < check.length; k++){
        check[k].classList.remove("high");
    }
}

function unexpected(){
    var check= document.getElementsByClassName("high");
		while(check.length > 0){
    		check[0].classList.remove("high");
		}
}