function changeSortOrder()
{
  orderBy = document.forms.sortForm.orderBy[document.forms.sortForm.orderBy.selectedIndex].value;
  window.location.href = orderBy;
}

function showSearchBox()
{
	document.getElementById("searchFloatContainer").style.display="block";
	document.getElementById("searchFloatContainer").style.zIndex=10;
	document.forms.quick_find.keywords.focus();
}

function showTopTen(divToShow)
{
  if (document.getElementById(divToShow).style.display == "none")
  {
    document.getElementById("homePopularTop5").style.display = "none";
	document.getElementById("homePopular6to10").style.display = "none";
	document.getElementById("homeNewestTop5").style.display = "none";
	document.getElementById("homeNewest6to10").style.display = "none";
	
	document.getElementById(divToShow).style.display = "block";
	
	if ((divToShow=="homePopularTop5") || (divToShow=="homeNewestTop5"))
	{
	  document.getElementById("homePopularAndNewPreviousNextLink").innerHTML = "Next 5";
	}
	else
	{
	  document.getElementById("homePopularAndNewPreviousNextLink").innerHTML = "Top 5";
	}
	
	if ((divToShow=="homeNewestTop5") || (divToShow=="homeNewest6to10"))
	{
	  document.getElementById("homeNewTab").src = "images/siteimages/home-new-products-on.gif";
	  document.getElementById("homePopularTab").src = "images/siteimages/home-top-sellers-off.gif";
	}
	else
	{
	  document.getElementById("homeNewTab").src = "images/siteimages/home-new-products-off.gif";
	  document.getElementById("homePopularTab").src = "images/siteimages/home-top-sellers-on.gif";
	}
  }
}

function toggleTopTen()
{
  if (document.getElementById("homePopularTop5").style.display == "block") showTopTen("homePopular6to10");
  else if (document.getElementById("homePopular6to10").style.display == "block") showTopTen("homePopularTop5");
  else if (document.getElementById("homeNewestTop5").style.display == "block") showTopTen("homeNewest6to10");
  else if (document.getElementById("homeNewest6to10").style.display == "block") showTopTen("homeNewestTop5");
}

function checkForm()
{
  if (document.getElementById('enquiryFormName').value == "")
  {
    alert ('Please enter your name.');
    document.getElementById('enquiryFormName').focus();
    return false;
  }
  else if ((document.getElementById('enquiryFormEmail').value == "") && (document.getElementById('enquiryFormTelephone').value == ""))
  {
	  alert ('Please enter either your Telephone Number or Email address.');
	  document.getElementById('enquiryFormEmail').focus();
      return false;
  }
  else if (document.getElementById('enquiryFormEmail').value != "")
  {
    if (checkEmailAddress(document.getElementById('enquiryFormEmail').value) == false)
    {
      alert ('Please enter a valid Email address.');
	  document.getElementById('enquiryFormEmail').focus();
      return false;
	}
  }
  if (document.getElementById('enquiryFormMessage').value =="")
  {
	alert ('Please tell us how we can help.');
	document.getElementById('enquiryFormMessage').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);
}