function switchLightBox()
{
	lightboxSrc = document.getElementById("homeButtonPrintDesign").src;
	
	lastSevenCharacters = lightboxSrc.substring(lightboxSrc.length, (lightboxSrc.length - 7))
	
    //alert(lastSevenCharacters);
	
	if (lastSevenCharacters == "off.jpg")
	{
	  document.getElementById("homeButtonPrintDesign").src = "../images/home-button-exhibitions.jpg";
	}
	else
	{
	  document.getElementById("homeButtonPrintDesign").src = "../images/home-button-exhibitions-off.jpg";
	}
}

function changeImage(urlOfImage)
{
  document.getElementById("mainProductImage").src = "product_thumb.php?img="+urlOfImage+"&w=320";
}

defaultSearchText = "search";

function showSearchBox()
{
  document.getElementById("headerSearchButton").style.display="none";
  document.getElementById("headerSearchButton").style.zIndex=1;
  document.getElementById("searchBoxContainer").style.display="block";
  document.getElementById("searchBoxContainer").style.zIndex=2;
  document.forms.quick_find.keywords.focus();
}

function trim(stringToTrim)
{ 
  while (stringToTrim.substring(0,1) == ' ') stringToTrim = stringToTrim.substring(1, stringToTrim.length);
  while (stringToTrim.substring(stringToTrim.length-1,stringToTrim.length) == ' ') stringToTrim = stringToTrim.substring(0, stringToTrim.length-1);
  return stringToTrim;
} 


function clearSearchBox(inputBox)
{
  if (trim(document.getElementById(inputBox).value) == defaultSearchText)
  {
    document.getElementById(inputBox).value = "";
  }
}

function insertDefaultSearchText(inputBox)
{
  if (trim(document.getElementById(inputBox).value) == "")
  {
    document.getElementById(inputBox).value = defaultSearchText;
  }
}


function checkForm()
{
  if (document.forms.rightColumnForm.realname.value == "")
  {
    alert ('Please enter your name.');
    document.forms.rightColumnForm.realname.focus();
    return false;
  }
  else if (document.forms.rightColumnForm.email.value == "")
	{
	  alert ('Please enter your Email address.');
	  document.forms.rightColumnForm.email.focus();
      return false;
	}
	else if (checkEmailAddress(document.forms.rightColumnForm.email.value) == false)
	{
      alert ('Please enter a valid Email address.');
	  document.forms.rightColumnForm.email.focus();
    return false;
	}
  else if (document.forms.rightColumnForm.message.value == "")
  {
	alert ('Please enter your message.');
	document.forms.rightColumnForm.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);
}