JSFiddle - React, Tailwind, and code Playground

HTML

<p class="para">
My house is red and my front door is blue.
</p>

CSS

.matched {
  background-color: red;
  font-weight: bold;
}

JavaScript

(function() {
	var paragraph = document.getElementsByClassName('para')[0];
  var text = paragraph.innerHTML;

  var wordArr = text.split(' ');
 	text = [];
  wordArr.forEach(function(el) {
  	if(el === 'house' || el === 'red')
    	el = '<span class="matched">' + el + '</span>';
    text.push(el);
  });
  console.log(text);
  text = text.join(' ');
  paragraph.innerHTML = text;
})()