var num;
num=0;
setTimeout('change_img()',1000);
function change_img(){
if(num>3) num=0;
setTimeout('setFocus('+num+')',10000);
num++;
tt=setTimeout('change_img()',20000);
} 
function setFocus(id)
{
selectLayer(id);
}
function selectLayer(id)
{
var layers=[document.getElementById("inhdpd1"),document.getElementById("inhdpd2"),document.getElementById("inhdpd3"),document.getElementById("inhdpd4")];
var layernavs=[document.getElementById("inhdp1"),document.getElementById("inhdp2"),document.getElementById("inhdp3"),document.getElementById("inhdp4")];
for(var i=0;i<layers.length;i++)
{
if(i==id)
{
layernavs[i].className="on";
layers[i].style.display="block";
}
else
{
layernavs[i].className="";
layers[i].style.display="none";
}
}
}