JSFiddle - React, Tailwind, and code Playground

HTML

<ul id='flash-menu'>
<li id="menu1" class='something active'>item 1</li>
<li id="menu2" class='somethingelse'>item 2</li>
<li id="menu3" class='somethingelse'>item 3</li>
</ul>

CSS

.active {color: red}

JavaScript

var list_items = document.getElementById('flash-menu').childNodes; 
for (var i=0 ; i<list_items.length ; i++){
    var elm = list_items[i];
    if (elm.className) {
        elm.className = elm.className.replace(/\bactive\b/,'');
    }
    }
//document.getElementById(view_name).className += " active";