DOM: get the first child of a DOM element

first.js

var util = {};

/* now: we use this one */
util.first = function(element) {
  if(!element) return;
  return element[element.firstElementChild ? 'firstElementChild' : 'firstChild'];
}

/* former: */
util.first = function(element) {
  if(!element) return;
  
  var first= element.firstChild;
  while(first && first.nodeType !==1) first = first.nextSibling;
  return first;
}

/* directly select */
util.first = function(element, tag) {
  if(!element) return;
  tag = tag || '*';
  return element.querySelector ? element.querySelector(tag) : element.getElementsByTagName(tag)[0];
}

/* children selector */
util.first = function(element) {
  return element && element.children[0];
}