function ost()
{
 document.getElementById('ost').setAttribute("class", "boxa");
 document.getElementById('ost_t').style.display='block';
 
 document.getElementById('nast').setAttribute("class", "boxb");
 document.getElementById('nast_t').style.display='none';
 
}

function nast()
{
 document.getElementById('ost').setAttribute("class", "boxb");
 document.getElementById('ost_t').style.display='none';
 
 document.getElementById('nast').setAttribute("class", "boxa");
 document.getElementById('nast_t').style.display='block';
 
}



function tab()
{
 document.getElementById('tab').setAttribute("class", "boxa");
 document.getElementById('tab_t').style.display='block';
 
 document.getElementById('tabs').setAttribute("class", "boxb");
 document.getElementById('tabs_t').style.display='none';
 
}

function tabs()
{
 document.getElementById('tab').setAttribute("class", "boxb");
 document.getElementById('tab_t').style.display='none';
 
 document.getElementById('tabs').setAttribute("class", "boxa");
 document.getElementById('tabs_t').style.display='block';
 
}




function bbt()
{
 document.getElementById('bbt').setAttribute("class", "boxbba");
 document.getElementById('bbtt').style.display='block';
 
 document.getElementById('bbl').setAttribute("class", "boxbbb");
 document.getElementById('bblt').style.display='none';
 
}

function bbl()
{
 document.getElementById('bbt').setAttribute("class", "boxbbb");
 document.getElementById('bbtt').style.display='none';
 
 document.getElementById('bbl').setAttribute("class", "boxbba");
 document.getElementById('bblt').style.display='block';
 
}





function gal()
{
 document.getElementById('gal').setAttribute("class", "pba1");
 document.getElementById('gal_t').style.display='block';
 
 document.getElementById('video').setAttribute("class", "pba2");
 document.getElementById('video_t').style.display='none';
 
}

function video()
{
 document.getElementById('gal').setAttribute("class", "pba2");
 document.getElementById('gal_t').style.display='none';
 
 document.getElementById('video').setAttribute("class", "pba1");
 document.getElementById('video_t').style.display='block';
 
}