JSFiddle - React, Tailwind, and code Playground

HTML

<div id='xx'>
    <span style='font-size:10px;font-family: arial,impact;color:red;'>Moj wklejany tekst</span>
</div>
<div id='yy'>
    <p style="margin-bottom: 0cm">
        <font face="Courier 10 Pitch, cursive">Kkkkkkkkkkkkkkkkkkkkkkk</font>
        <font face="Comic Sans MS">ssssssssssssss</font>
        <font face="Impact, sans-serif">qqqqqqqqqqqqqqqqqqq</font>
    </p>
</div>
<div id='zz'></div>

JavaScript

$(document).ready(function() {
    var x = $("#xx").html();
    //var xxx = x.match(/font-family\:(.+?);/);
    var xxx = x.match(/font\:(.+?);/);
    if (xxx != null) alert(xxx);
    //alert(x.replace(/font-family\:(.+?);/,""));
    var y = $("#yy").html();
    var yyy = y.match(/\sface=\"([a-zA-Z0-9\u002C\s\-]*)\"/g);
    if (yyy != null) alert(yyy);
    var n = y.replace(/\sface=\"([a-zA-Z0-9\u002C\s\-]*)\"/g,"");
    alert(n);
    $("#zz").html(n);
});