function hide() {
var divs = document.getElementsByTagName("div");
divs[0].style.display = 'none';
divs[1].style.display = 'none';
divs[2].style.display = 'none';
divs[3].style.display = 'none';
}
function show() {
var divs = document.getElementsByTagName("div");
divs[0].style.display = 'block';
divs[1].style.display = 'block';
divs[2].style.display = 'block';
divs[3].style.display = 'block';
}
function blopp(which) {
hide();
var divs = document.getElementsByTagName("div");
divs[which].style.display = 'block';
}