JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>tddafextasdasdsad</li>
</ul>
<div id="divResult" style="margin-left: 15px"></div>

CSS

.redbold {
    font-weight: bold;
    color: red;
}

JavaScript

var dt = new Date("11/22/2015");

var today = new Date();
var newText = "";
var dateDiffDays = Math.ceil((Math.ceil(dt.getTime() - today.getTime())) / (1000 * 3600 * 24));
if (dateDiffDays >= -10 && dateDiffDays <= 10) {
    console.log('NEW - date within 10 days');
    //newText = "<font color='red'><b>NEW - </b></font>";
    newText = "<span class='redbold'>NEW - </span>";
} else {
    console.log('OLD');
    newText = "";
}


$("#divResult").html(newText);