Why does the script not see the function in setInterval?

Question

JavaScript

Hello!
Tell me why if you just type this code into the console, it works, and the button is created as part of the extension, but when pressed, it displays:

1 Uncaught ReferenceError: functionName is not defined

function functionName() {
alert('Имя') 
}

setInterval(() => {
document.querySelector('.button').innerHTML = '<button onclick="functionName()" type="button" >Показывать имя</button>' 
}, 1000)

Hope I phrased the question well.

Answer 1

The function functionNameexists in the context of the script content.
When adding a button with a click on it, it will be called in the context of a web page where this function does not exist. 1. Add a button. 2. Add an event listener through it. Will work. onclick="functionName()"functionName