Why wouldn't node.js recognize my index.html reference in the script.js file?

Pardon me for the dumb question but I couldn't find any fix and I've done copied perfectly a script from a YouTube tutorial and they seem to have no problem (neither do others, same method) but when I get to run node script.js in the terminal (or refreshing the html page in browser) nothing seems to work as it should and the html page remains static. I tried browsify and jsdom and what other suggested before in here but I wasted the same time with those too.

So here it is, even put it twice, once above </body> and once above </head>:

<script scr="script.js"defer></script>
...
    <div class="countdown-days-c">
        <p class="big-text"id="days">0</p>
        <span>days</span>
    </div>

And in the JS file like:

const daysElement = document.getElementById("days");

followed by this error

ReferenceError: document is not defined
    at Object.<anonymous> (C:\Users\......\script.js:6:16)
    at Module._compile...

and so on. Maybe I just missed something but I did exactly as shown and I've been struggling with this for some time now. I don't have any problem with the CSS file and the JS file can run perfectly standalone, but can't seem to work with the HTML.