function start() 
{
	document.getElementById('portfolio').style.display = "none";
	document.getElementById('about').style.display = "block";
	document.getElementById('contact').style.display = "none";
	document.getElementById('login').style.display = "none";
}

function about() 
{
	document.getElementById('portfolio').style.display = "none";
	document.getElementById('about').style.display = "block";
	document.getElementById('contact').style.display = "none";
	document.getElementById('login').style.display = "none";
}

function portfolio() 
{
  document.getElementById('portfolio').style.display = "block";
	document.getElementById('about').style.display = "none";
	document.getElementById('contact').style.display = "none";
	document.getElementById('login').style.display = "none";
}

function contact() 
{
  document.getElementById('portfolio').style.display = "none";
	document.getElementById('about').style.display = "none";
	document.getElementById('contact').style.display = "block";
	document.getElementById('login').style.display = "none";
}

function login() 
{
  document.getElementById('portfolio').style.display = "none";
	document.getElementById('about').style.display = "none";
	document.getElementById('contact').style.display = "none";
	document.getElementById('login').style.display = "block";
}