function BlackScreen(idscreen,idiframe,idcont)
{
document.getElementById(idscreen).style.top= '0px';
document.getElementById(idiframe).style.top= '0px';
document.getElementById(idscreen).style.display= 'block';
document.getElementById(idiframe).style.display= 'block';
//document.getElementById(idcont).style.top='0px';
document.getElementById(idcont).style.display= 'block';
}
function BlackScreenOff(idscreen,idiframe,idcont)
{
document.getElementById(idscreen).style.display= 'none';
document.getElementById(idiframe).style.display= 'none';
document.getElementById(idcont).style.display= 'none';
}