Cacher une classe en Javascript

function getElementsByClass(searchClass, node, tag)
{
  var classElements = new Array();
  if(node == null) node = document;
  if(tag == null) tag = '*';
  
  var els = node.getElementsByTagName(tag);
  var elsLen = els.length;
  var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
  
  for(i = 0, j = 0; i < elsLen; i++)
  {
    if(pattern.test(els[i].className) )
      { 
        classElements[j] = els[i];
        j++;
      }
  }
  
  return classElements;
}

function hiddenByClass(searchClass, node, tag)
{
 
	var elm = getElementsByClass(searchClass, node, tag);
	
	for(var i = 0; i < elm.length; i++)
	{
		elm[i].style.display = "none";
    }
}