JSFiddle - React, Tailwind, and code Playground

HTML

<p id = 'out'>
start
</p>

JavaScript

var a = 1;

function foo (proxy){
    print(proxy);
}

function print(out){
    document.getElementById("out").innerHTML = out;
}

// foo("you")

print(d); // undefined

var d = 4;

print(d); // 4