JSFiddle - React, Tailwind, and code Playground

HTML

<div class="line" id="1">1</div>
<div class="line" id="20">20</div>
<div class="line" id="5">5</div>
<div class="line" id="2">2</div>
<div class="line" id="99">99</div>

JavaScript

var adder = document.getElementsByClassName("line");             
for(var i = 0 ;i<adder.length;i++){         
    var item = adder.item(i);
    if (parseInt(item.id) >= 10)
        item.style.color="red";
    console.log(parseInt(item.id));
}