function swpic(chi,chp)
{
document.getElementById(picid[chi]).src=pics[chp]
}
function swbtn(btn)
{
 
 var drh1 = document.getElementById(btn);
 var bg1 = drh1.getAttributeNode("class");
 bg1.value="act_nav";

}
function sw2btn(btn)
{
 var drh1 = document.getElementById(btn);
 var bg1 = drh1.getAttributeNode("class");
 bg1.value="nav_main";
}