Did I create a cookie incorrectly?

Question

JavaScript

Hello. I want to create cookies, the code seems to be correct, but it doesn't work, what's the matter?

<form>
  <input type="text" id="first" placeholder="Введите имя">
  <input type="button" id="done" value="Готово!">
</form>

<script>
  var init = function() {
  var expDate = new Date();
  expDate.setMonth(expDate.getMonth() +1);
  var cookieVal = document.getElementById("first").value;
  document.cookie = "first" + "=" + cookieVal + ";path=/;expires=" + expDate.toGMTString();
}
document.getElementById("done").onclick = init();
</script>

Answer 1

document.getElementById("done").onclick = init;
If you put brackets after a variable that refers to a function, then you call this function, which means you pass the result of its execution. You don't need to put parentheses to pass the function itself.