This function defines an HTML element. document.getElementById returns the complete function, not only the h1 element as expected. How I only write what's inside of the two ` (return value).
function tokens() {
return `
<h1>test</h1>
`;
}
document.getElementById('tokens').innerHTML = tokens;
Change
document.getElementById('tokens').innerHTML = tokens;
to
document.getElementById('tokens').innerHTML = tokens();
You have to call the function with parentheses () in order for it to execute and return the proper output:
document.getElementById('tokens').innerHTML = tokens();
You've written tokens as if it is a variable. Since you want to run a function, add () to tokens. That would be tokens().