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>');
$(header[header.length-1]).css({width:"+=20"});
alert(header);