Recursive method to find elements by class name

getElementsByClassName.js

function getElementsByClassName(className) {
  var elements = document.body,
      matches  = [];

  function traverse(node) {
    for(var i = 0; i < node.childNodes.length; i++) {
      if(node.childNodes[i].childNodes.length > 0) {
        traverse(node.childNodes[i]);
      }
      
      if(node.childNodes[i].getAttribute && node.childNodes[i].getAttribute('class')) {
        if(node.childNodes[i].getAttribute('class').split(" ").indexOf(className) >= 0) {
          matches.push(node.childNodes[i]);
        }
      }
    }
  }
  
  traverse(elements);
  return matches;
    
}
getElementsByClassName('some-class');

you should switch the order of the conditionals on line 7 with the one on line 11 otherwise the order is a little starts from the bottom up . unless you intended that.