function changeClass(lang) 
{
  switch(lang)
  {
    case "ua":
      document.getElementById("lang_ua").className = "active";
      document.getElementById("lang_en").className = "no_active";
      break
    case "en":
      document.getElementById("lang_ua").className = "no_active";
      document.getElementById("lang_en").className = "active";    
      break
  }
}