// funçoes para manipular classes de objetos DOM // 

function getArrayFromClasses( obj ) {
  var classes = obj.className.split(" ");
  if( classes.length == 1 && classes[0] == "" )
  {
    classes = new Array();
  }

  return classes;
}

function setClassesStringFromArray( classes ) {
  return classes.join(" ");
}

function addClass( obj, className )
{
  var classes = getArrayFromClasses( obj );
  classes.push( className );
  obj.className = setClassesStringFromArray( classes ); }

function removeClass( obj, className )
{
  var classes = getArrayFromClasses( obj );
  for(i in classes)
  {
    if(classes[i] == className)
    {
      classes.splice(i,1);
    }
  }
  obj.className = setClassesStringFromArray( classes ); }

function clearClasses( obj )
{
  var classes = new Array();
  obj.className = setClassesStringFromArray( classes ); }

function existsClass( obj, className )
{
  var classes = getArrayFromClasses( obj );
  for(i in classes)
  {
    if(classes[i] == className)
    {
      return true;
    }
  }
  return false;
}


// Altera aba selecionada
function changeAba( obj )
{
  var ul = obj.parentNode.parentNode;
  var a = ul.getElementsByTagName("a");

  for(var i=0; i<a.length; i++)
  {
    removeClass( a[i], "ativo" );
	//addClass( a[i].parentNode.parentNode, "inativo" );
	
  }
  addClass( obj, "ativo" );
}