function show_div(n) {
 //if (window.opera) {} else {
 document.getElementById(n).style.visibility = "visible"; 
// document.n.style.visibility = "visible"; 

}

function hide_div(n) {
 //if (window.opera) {} else 
 document.getElementById(n).style.visibility = "hidden"; 
// document.n.style.visibility = "hidden"; 
}