ex02.1_variables.js

var globalGreeting = "Good ";

function testFunction() {
    var localGreeting = "Morning ";  
    console.log("function:");
    console.log(globalGreeting);
    console.log(localGreeting);
}

testFunction();

console.log("main program:");
console.log(globalGreeting);
console.log(localGreeting); // -> Uncaught ReferenceError: localGreeting is not defined