A short Javascript fragment for quickly adding the most common "click-submit-on-enter" functionality to an mTurk userscript.

mturk-vanilla-submit-on-enter-fragment.js

document.addEventListener("keyup", e => {
  const {key} = e;
  if(key === "Enter") {
    e.preventDefault();
    const submitButton = [
      document.querySelector("#submitButton"),
      document.querySelector("#SubmitButton"),
      document.querySelector("[type='submit']")
    ].find(el => !!el);
    el.click();
  }
});