How to write a JS function as a placeholder in a textarea correctly?

Question

I'm trying to write a JS function as a placeholder, but the browser thinks it's a JS instead of a simple placeholder for textarea.

How could this be done right?

<textarea placeholder="Paste some code..

while (!fileExists('properSolution.js') {
    var pureNS1 = unchanged; // no NS2 parts added manually
    var yourScript = the script you're going to convert

    if (yourScript == pureNS1) {
        clickButtonBelow('NS1 TO NS2');
    }
    else {
        clickButtonBelow('NS2 TO NS1'); //Prevents duplicates
        clickButtonBelow('NS1 TO NS2');
    }
    sleep(2022);
}"></textarea>

This JS is supposed to serve as a note only/placeholder.

Thank you in advance!