function setPage(page)
{
  document.getElementById('nav'+page).src="images/nav-"+page+"-on.gif";
}

function popUpWin(url,name,width,height,scrollbars)
{
  var windowParameters = "width="+width+",height="+height+
                         ",scrollbars="+scrollbars+",status=no,resizable=yes,top=20,left=20";
  var poUpWin = window.open(url,name,windowParameters);
}

function map()
{
  popUpWin("map.html","williamhousemap",600,539,"no");
}

function showHide()
{

  if (document.forms.contactForm.contactMeBy[0].checked == true)	
  {
    divToShow = "email";  
  }
  else if (document.forms.contactForm.contactMeBy[1].checked == true)	
  {
    divToShow = "telephone";  
  }
  else
  {
    divToShow = "none";  
  }
  

  if (divToShow == "email")
  {
	document.getElementById('telephoneNumber').style.display="none";
	document.getElementById('emailAddress').style.display="block";
  }
  else if (divToShow == "telephone")
  {
	document.getElementById('emailAddress').style.display="none";
	document.getElementById('telephoneNumber').style.display="block";  
  }
  else
  {
	document.getElementById('telephoneNumber').style.display="none";
	document.getElementById('emailAddress').style.display="none";
  }
}

function checkForm()
{
  if (document.forms.contactForm.realname.value == "")
  {
    alert ('Please enter your name.');
    document.forms.contactForm.realname.focus();
    return false;
  }
  else if ((document.forms.contactForm.contactMeBy[0].checked==false) && (document.forms.contactForm.contactMeBy[1].checked==false))
  {
    alert ('Please tell us how you\'d like us to contact you.');
	document.forms.contactForm.contactMeBy[0].focus();
	return false;
  }
  else if (document.forms.contactForm.contactMeBy[0].checked)
  {
	if (document.forms.contactForm.email.value == "")
	{
	  alert ('Please enter your Email address.');
	  document.forms.contactForm.email.focus();
      return false;
	}
	else if (checkEmailAddress(document.forms.contactForm.email.value) == false)
	{
      alert ('Please enter a valid Email address.');
	  document.forms.contactForm.email.focus();
    return false;
	}
  }
  else if (document.forms.contactForm.telephone.value == "")
  {
    alert ('Please enter your telephone number.');
	  document.forms.contactForm.telephone.focus();
	      return false;
  }
  else if (document.forms.contactForm.message.value == "")
  {
	alert ('Please enter your message.');
	document.forms.contactForm.message.focus();
	    return false;
  }
  else
  {
    return true;	  
  }
}

function checkEmailAddress(emailAddress)
{
  var allowed = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.@-_";
  var emailLength = emailAddress.length;
  var atSignPosition = 0;
  var finalDotPosition = 0;
  var numberOfDots = 0;
  var numberOfAtSigns = 0;

  if (emailLength < 5)
  {
    return false;
  }

  for (i = 0; i < emailLength ;i ++)
  {
    if (allowed.indexOf(emailAddress.charAt(i))<0)
    {
      return (false);
    }
    if ((emailAddress.charAt(i)) == "@")
    {
      numberOfAtSigns ++;
      atSignPosition = i;
    }
    else
    {
      if ((emailAddress.charAt(i)) == ".")
      {
        numberOfDots ++;
        finalDotPosition = i;
      }
    }
  }
  if (numberOfDots == 0)
  {
    return (false);
  }
  if (numberOfAtSigns != 1)
  {
    return (false);
  }
  if (atSignPosition > finalDotPosition)
  {
    return (false);
  }
  if (finalDotPosition == (emailLength-1))
  {
    return (false);
  }
  return (true);
}