function SearchBoxOnFocus() {
  document.getElementById('search_box').className = 'searchbox_active';
  document.getElementById('search_box').value = '';
}

function SearchBoxOnBlur() {
  /*
  document.getElementById('search_box').className = 'searchbox_inactive';
  document.getElementById('search_box').value = 'Строка поиска';
  */
}

function PostForm() {
  if (window.event.keyCode == 13) {
    document.search_form.post;
  }
}