function show (t) {
//   document.getElementById(t).style.visibility = "visible";
//   document.getElementById(t).style.display = "block";
alert ("show");
}

function show2 (t) {
   document.getElementById(t).style.display = "block";
}
function hide (t) {
   document.getElementById(t).style.visibility = "hidden";
}
function hide2 (t) {
   document.getElementById(t).style.display = "none";
}

function change_source (e, s) {
   document.getElementById(e).src = s;
}