function main() {
	var contact = document.getElementById("contact");
	contact.className = 'hidden'; 
	var buy = document.getElementById("buy");
	buy.className = 'hidden'; 
	var buy = document.getElementById("sell");
	buy.className = 'hidden'; 
	var buy = document.getElementById("estate");
	buy.className = 'hidden'; 
}

function contact() {
	var contact = document.getElementById("contact");
	contact.className = 'visible'; 
}

function buy() {
	var buy = document.getElementById("buy");
	buy.className = 'visible'; 
}

function sell() {
	var buy = document.getElementById("sell");
	buy.className = 'visible'; 
}

function estate() {
	var buy = document.getElementById("estate");
	buy.className = 'visible'; 
}