function tyt1() {
document.getElementById('tyt_a').style.background='url(/images/one_b.jpg)';
document.getElementById('tyt_b').style.background='url(/images/two_a.jpg)';
document.getElementById('tyt_c').style.background='url(/images/three_a.jpg)';
document.getElementById('tyt_d').style.background='url(/images/four_a.jpg)';
document.getElementById('tyt_1').style.display='block';
document.getElementById('tyt_2').style.display='none';
document.getElementById('tyt_3').style.display='none';
document.getElementById('tyt_4').style.display='none';
}
function tyt2() {
document.getElementById('tyt_a').style.background='url(/images/one_a.jpg)';
document.getElementById('tyt_b').style.background='url(/images/two_b.jpg)';
document.getElementById('tyt_c').style.background='url(/images/three_a.jpg)';
document.getElementById('tyt_d').style.background='url(/images/four_a.jpg)';
document.getElementById('tyt_1').style.display='none';
document.getElementById('tyt_2').style.display='block';
document.getElementById('tyt_3').style.display='none';
document.getElementById('tyt_4').style.display='none';
}
function tyt3() {
document.getElementById('tyt_a').style.background='url(/images/one_a.jpg)';
document.getElementById('tyt_b').style.background='url(/images/two_a.jpg)';
document.getElementById('tyt_c').style.background='url(/images/three_b.jpg)';
document.getElementById('tyt_d').style.background='url(/images/four_a.jpg)';
document.getElementById('tyt_1').style.display='none';
document.getElementById('tyt_2').style.display='none';
document.getElementById('tyt_3').style.display='block';
document.getElementById('tyt_4').style.display='none';
}
function tyt4() {
document.getElementById('tyt_a').style.background='url(/images/one_a.jpg)';
document.getElementById('tyt_b').style.background='url(/images/two_a.jpg)';
document.getElementById('tyt_c').style.background='url(/images/three_a.jpg)';
document.getElementById('tyt_d').style.background='url(/images/four_b.jpg)';
document.getElementById('tyt_1').style.display='none';
document.getElementById('tyt_2').style.display='none';
document.getElementById('tyt_3').style.display='none';
document.getElementById('tyt_4').style.display='block';
}