JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="Say Hello!" onclick="sayHello()" />

JavaScript

function sayHello(name){
    alert("Hello, " + name + "!");
}

(function (w){
    var sayHelloOld = w.sayHello;
    
    w.sayHello = function (){
        var name = prompt("Enter your name");
        sayHelloOld.apply(this, [name]);
    }
})(window);