function elem(text) {

  var el = document.createElement('span');

  try {

    el.textContent = text;

  } catch (err) {}

  try {

    el.innerText = text;

  } catch (err) {}

  return el;

}

​

window.onload = function () {

  var a = document.getElementById('a');

  try { a.insertAdjacentElement('beforebegin', elem('1st (out)')); } catch (e) {}

  try { a.insertAdjacentElement('afterbegin', elem('2nd (in)')); } catch (e) {}

  try { a.insertAdjacentElement('beforeend', elem('4th (in)')); } catch (e) {}

  try { a.insertAdjacentElement('afterend', elem('5th (out)')); } catch (e) {}

  var b = document.getElementById('b');

  try { b.insertAdjacentText('beforebegin', '1st (out)'); } catch (e) {}

  try { b.insertAdjacentText('afterbegin', '2nd (in)'); } catch (e) {}

  try { b.insertAdjacentText('beforeend', '4th (in)'); } catch (e) {}

  try { b.insertAdjacentText('afterend', '5th (out)'); } catch (e) {}

};