In that case you would be wanting to get the calculator code from a cdn so that it can be added into resources.

Here’s one from https://cdnjs.cloudflare.com/ajax/libs/mathjs/9.4.4/math.min.js

The details are found at https://mathjs.org/

But basically, eval can be replaced with math.evaluate instead.

`getElementById('result').value = math.evaluate(getElementById('input').value)`

The minimal change code is found at https://jsfiddle.net/y34te1aL/

I’ve also moved the inline onclick code out of the HTML and into the JS section and tidied up the JS code, resulting in the following:

```
/*global math */
const button = document.querySelector("button");
button.addEventListener("click", function () {
const input = document.querySelector("#input");
const result = document.querySelector("#result");
result.value = math.evaluate(input.value);
});
```

The updated code can be found at https://jsfiddle.net/y34te1aL/1/