function clearmenue()
{
  for(i=1;i<= 6;i++)
  {
    if(document.getElementById('navig'+i)) document.getElementById('navig'+i).style.display = 'none';
  }
}

function show(get)
{
  clearmenue();
  
  if(document.getElementById(get) && document.getElementById(get).style.display != 'block')
  {
    document.getElementById(get).style.display = 'block';
  }

}

function hide(get)
{
  if(document.getElementById(get).style.display != 'none')
  {
    document.getElementById(get).style.display = 'none';
  }

}


function change_visibility(get)
{
  if(document.getElementById(get).style.display == 'none')
    document.getElementById(get).style.display = '';
    else 
    document.getElementById(get).style.display = 'none';

}