function show(id) {
    var obj = document.getElementById(id);
    obj.style.visibility = 'visible';
}

function hide(id) {
    var obj = document.getElementById(id);
    obj.style.visibility = 'hidden';
}

function displayBlock(id) {
    var obj = document.getElementById(id);
    obj.style.display = 'block';
}

function displayNone(id) {
    var obj = document.getElementById(id);
    obj.style.display = 'none';
}