var active=1;

function zobraz(id){
active=id;
var medium = document.getElementById("medium");
var mini = document.getElementById("mini");

var obrazky_med = medium.getElementsByTagName("img");
var obrazky_min = mini.getElementsByTagName("img");

for(var i=1; i<=obrazky_med.length; i++){
document.getElementById('m_'+i).style.display='none';
}
document.getElementById('m_'+id).style.display='block';
var vyska = document.getElementById('m_'+id).offsetHeight;
if(vyska>510){
document.getElementById("frame").style.height=(vyska+40)+"px";
}else{
document.getElementById("frame").style.height=530+"px";
}

for(var i=1; i<=obrazky_min.length; i++){
document.getElementById('s_'+i).style.border='2px solid #000000';
}
document.getElementById('s_'+id).style.border='2px solid #ff0000';

}

function pred(){
if(document.getElementById('m_'+(active-1))){
zobraz((active-1));
}else{
var last = document.getElementById("mini").getElementsByTagName("img").length;
zobraz(last);
}
}

function dal(){
if(document.getElementById('m_'+(active+1))){
zobraz((active+1));
}else{
zobraz(1);
}
}

function otevri(id){
document.getElementById('frame').style.display='block';
zobraz(id);
}


function zavri(){
document.getElementById('frame').style.display='none';
}