what will happen if we use callback function in javascript code example

Example 1: callback function js

function greeting(name) {
  alert('Hello ' + name);
}

function processUserInput(callback) {
  var name = prompt('Please enter your name.');
  callback(name);
}

processUserInput(greeting);

Example 2: callback functions javascript

function isOddNumber(number) {
    return number % 2;
}Code language: JavaScript (javascript)