replaceChild, just like removeChild returns the replaced or removed node
/*
#   replace text node
#   =================
*/
  var divB = document.getElementById('B').firstChild; 
  var newText = document.createTextNode('buddy'); 
  divB.parentNode.replaceChild(newText, divB);
/*
#  both replaceChild() and removeChild() return the replaced or removed node
#
*/