function mostradx(a) {
document.getElementById(a).style.display="block";
var x = window.screen.width;
var posx = x - 300;
document.getElementById(a).style.left=posx+"px";
}
function nascondi(a) {
document.getElementById(a).style.display="none";
}
function mostra(a) {
document.getElementById(a).style.display="block";
}