function getValue()
  {
  document.getElementById("myHeader").style.display = "block";
  } 
  
function getValue2()
  {
  document.getElementById("myHeader").style.display = "none";
  } 
  
  function changeimage()
{
document.getElementById('homeimage').src="images/headerphoto0" + (Math.floor(Math.random()*4)) + ".jpg"; 
}