JSFiddle - React, Tailwind, and code Playground

HTML

<button id="myfunction">Alert hello</button>
<button id="mystopfunction">Stop before 3 seconds</button>

JavaScript

var myVar;

$(document).ready(function(){
    $("#myfunction").click(function(){
        myFunction();
    });
    $("#mystopfunction").click(function(){
        myStopFunction();
    });
    function myFunction() {
        myVar = setTimeout(function(){
            alert("Hello")
        }, 3000);
    }
    
    function myStopFunction() {
        clearTimeout(myVar);
    }
});