var tabular_tab_count = 5;
var current_tab = 0;

function make_active(tab_index)
{
  $('tabular_brd_' + String(tab_index)).className = (tab_index != 0) ? 'order_brd_green_open_active' : 'order_brd_begin_active';
  $('tabular_tail_' + String(tab_index)).className = 'order_active';
  $('tabular_brd_' + String(Number(tab_index) + 1)).className = (tab_index != tabular_tab_count - 1) ? 'order_brd_active_blue_open' : 'order_brd_active_end';
}

function make_green(tab_index)
{
  for(i=0;i<tab_index;i++)
  {
    $('tabular_brd_' + String(i)).className = (i != 0) ? 'order_brd_green_closed_green_open' : 'order_brd_begin_green_closed';
    $('tabular_tail_' + String(i)).className = 'order_green';
  }
}

function make_blue(tab_index)
{
  for(i=tab_index+1;i<tabular_tab_count;i++)
  {
    $('tabular_tail_' + String(i)).className = 'order_blue';
    $('tabular_brd_' + String(Number(i) + 1)).className = (i != tabular_tab_count - 1) ? 'order_brd_blue_closed_blue_open' : 'order_brd_blue_closed_end';
  }
}

function show_content(tab_index)
{
  for(i=0;i<tabular_tab_count;i++)
  {
    $('tabular_content_' + String(i)).style.display = (i == tab_index) ? 'block' : 'none';
  }
}

function switch_tab(tab_index)
{
  make_active(tab_index);
  make_green(tab_index);
  make_blue(tab_index);
  $('tabular_corn_top_left').className = (tab_index != 0) ? 'corner_left_green' : 'corner_left_active';
  $('tabular_corn_top_right').className = (tab_index != tabular_tab_count - 1) ? 'corner_right_blue' : 'corner_right_active';
  show_content(tab_index);
}

function next_tab()
{
  if(current_tab < tabular_tab_count - 1)
  {
    switch_tab(++current_tab);
  }
}

function prev_tab()
{
  if(current_tab > 0)
  {
    switch_tab(--current_tab);
  }
}