function pressEnter(element){
  if(!(element instanceof EventTarget))
    element = document.querySelector(element) || document.body || document;

  var options = {
    bubbles: true,
    cancelable: true,
    charCode: 0,
    code: "Enter",
    key: "Enter",
    keyCode: 13,
    view: window,
    which: 13
  };

  ['keydown', 'keypress', 'keyup'].forEach(
    type => element.dispatchEvent(
      new KeyboardEvent(type, options)
    )
  );
}
setInterval(
  () => pressEnter('body'), //нажимаем enter на body
  5 * 1000 //раз в пять секунд
);