JSFiddle - React, Tailwind, and code Playground

HTML

<table id="motsCles">
  <tr><td>mot_clef_1</td></tr>
  <tr><td>mot_clef_2</td></tr>
</table>
 
<p id="texte">
Texte avec mot_clef_1 Ă  surligner
</p>

JavaScript

var motsCles = document.querySelectorAll("#motsCles td");
var texte = document.getElementById("texte");
var texteInitial = texte.innerHTML;
 
for(var m=0; m<motsCles.length; m++){
    (function(motCle){
            motCle.addEventListener("mouseover", function(){
               surbrillance(texte, motCle.innerText || motCle.textContent);
            });
             motCle.addEventListener("mouseout", function(){
               texte.innerHTML = texteInitial;
            });
    })(motsCles[m]);
}

function surbrillance(ou,quoi){
	var StrReg="("+quoi+")";
	var Reg=new RegExp((StrReg),"gi")
	ou.innerHTML= ou.innerHTML.replace(Reg,'<span style="background-color:#53C5FE;">$1</span>')
}