javascript having problem in handling codes from html [closed]

There’s this code that can be applicable to html since it is from server side.

but in script, it cannot.

this is the code at html where the code works:

<span id="lang">#(main.language.toUpperCase())</span>

and this is the code in script that doesn’t work:

$('#lang').html(`<span>${main.language.toUpperCase}</span>`);

What do you think is the issue in js code?