function openLi(id) {
	// decide if we are opening or closing the li element..
	var el = document.getElementById("li_" + id);
	alterCSS("swap", el, "openNav", "closedNav");
}

function alterCSS(action,element,c1,c2)
{
  switch (action){
    case 'swap':
      element.className=!alterCSS('check',element,c1)?element.className.replace(c2,c1): element.className.replace(c1,c2);
    break;
    case 'add':
      if(!alterCSS('check',element,c1)){element.className+=element.className?' '+c1:c1;}
    break;
    case 'remove':
      var rep=element.className.match(' '+c1)?' '+c1:c1;
      element.className=element.className.replace(rep,'');
    break;
    case 'check':
      return new RegExp('\\b'+c1+'\\b').test(element.className)
    break;
  }
}