how to declare global function in javascript code example

Example 1: javascript define global variable

window.myGlobalVariable = "I am totally a global Var"; //define a global variable
var myOtherGlobalVariable="I too am global as long as I'm outside a function";

Example 2: global scope js

const color = 'blue'

const returnSkyColor = () => {
  return color; // blue 
};

console.log(returnSkyColor()); // blue