var secnets4 = (document.layers) ? 1 : 0;
var secie4 = (document.all) ? 1 : 0;
var secdom = (document.getElementById) ? 1 : 0;
var kvant=0;

nfs = new Array("l1", "l2", "l3", "l4", "l5", "l6");
pic=new Array(nfs.length);
for (i=0;i<nfs.length;i++) {
  pic[i]=new Image();
  pic[i].src=nfs[i];
  }

function layershide(){
  for (i=0;i<nfs.length;i++) {
    layer=nfs[i];
    if (secnets4) {
      document.layers[layer].visibility = "hide";
    } else if(secdom){
        document.getElementById(layer).style.visibility = "hidden";
    } else {
      document.all[layer].style.visibility = "hidden";
    }
  }
}


function fotosnavig(val) {
layershide();
if (val==1) kvant=0
else if (val==3) {
if (kvant==(nfs.length-1)) kvant=0
else kvant++;
} else {
if (kvant==0) kvant=(nfs.length-1)
else kvant--;
}
layer=nfs[kvant];
if(nfs.length>0){
if (secnets4) {
document.layers[layer].visibility = "show";
} else if(secdom){
document.getElementById(layer).style.visibility = "visible";
} else {
document.all[layer].style.visibility = "visible";
}
}
}