JSFiddle - React, Tailwind, and code Playground

CSS

th{
    background-color:gray;
}

JavaScript

var header="<th id="tblHeader_1" style="width: 80px;"><span>Id</span></th>
<th class="headerSortDown" id="tblHeader_2" style="width: 300px;"><span>Title</span></th>"
<th class="headerSortDown" id="tblHeader_3" style="width: 300px;"><span>Adress</span></th>";

//Increase last th width
header.find(th:last).css('width',currentwidth+20+'px');

alert(header);