function hideSelects()
{
var aSelects = document.getElementsByTagName( "select" );
var nSelects = aSelects.length;
for( var i=0; i<nSelects; i++ )
{
eSelect = aSelects[ i ];
eSelect.style.visibility = "hidden";
}
}

function showSelects()
{
var aSelects = document.getElementsByTagName( "select" );
var nSelects = aSelects.length;
for( var i=0; i<nSelects; i++ )
{
eSelect = aSelects[ i ];
eSelect.style.visibility = "visible";
}
}