JSFiddle - React, Tailwind, and code Playground

HTML

<a onclick="message1()">message1</a>
<a onclick="message2()">message2</a>

JavaScript

(function(){
  // message1
  // Uncaught ReferenceError: message1 is not defined
  function message1() {
    alert(1)
  }
  
  // message2
  window.message2 = () => {
    alert(2)
  }
})()