How do i fix this code

Question

I am making a code that removes everything but letters but it keeps saying cannot change value of undefined
here is the link
https://code.sololearn.com/WcMDZonBHspS/?ref=app

Answer 1

Your html file is fine except you're missing the l at the beginning of the word letters for the button.
The javascript below should help you to figure it out:

function Function() {
var p = document.getElementById("id");
var txt = p.innerHTML.slice(8); // .slice(8) removes the "x equals " from the beginning so all that is left is what the user input.
var regex = /[^a-z]/gi;
txt = txt.replace(regex, "");
p.innerHTML = txt;
}

Answer 2

thanks