Uncaught TypeError: lang is not a function [duplicate]

Answer 1

There is no reason to complicate (I really do not know why it does not work), but you can use:

• Add the alert directly in the input.

Result: https://jsfiddle.net/cmedina/h4m1qcoq/6/

or

Add listener to input

function lang() {
   alert("Hello, World! It's JavaScript this time");
}

document.getElementById('test').onclick = lang

Result: https://jsfiddle.net/cmedina/h4m1qcoq/7/