JSFiddle - React, Tailwind, and code Playground
HTML
<div>
<p>
bla blab rkejre bla bla rrerte ehere errt
</p>
<div>
CSS
.someclass {
color: red;
}
JavaScript
var yourstring="bla";
$('p:contains('+yourstring+')', document.body).each(function(){
console.log(this);
$(this).html($(this).html().replace(
new RegExp(yourstring, 'g'), '<span class=someclass>'+yourstring+'</span>'
));
});