function changeImage(newURL)
{
  document.getElementById('entryMainImage').src=newURL;
}

function checkSellCaravanForm()
{
  if (document.getElementById('caravanMake').value == "")
  {
    alert ('Please enter the caravan make.');
    document.getElementById('caravanMake').focus();
    return false;
  }
  else if (document.getElementById('caravanModel').value == "")
  {
    alert ('Please enter the caravan model.');
    document.getElementById('caravanModel').focus();
    return false;
  }
  else if (document.getElementById('caravanYear').value == "")
  {
    alert ('Please enter the year.');
    document.getElementById('caravanYear').focus();
    return false;
  }
  else if ((document.getElementById('caravanPoor').checked == false) &&
			(document.getElementById('caravanAverage').checked == false) &&
			(document.getElementById('caravanGood').checked == false) &&
			(document.getElementById('caravanExcellent').checked == false))
  {
    alert ('Please tick the box corresponding to your caravan\'s condition.');
    return false;
  }
  else if ((document.getElementById('caravanAwningNone').checked == false) &&
			(document.getElementById('caravanAwningFull').checked == false) &&
			(document.getElementById('caravanAwningPorch').checked == false))
  {
    alert ('Please tick the box corresponding to your caravan\'s awning.');
    return false;
  }
  else if ((document.getElementById('caravanMotorMoverYes').checked == false) &&
			(document.getElementById('caravanMotorMoverNo').checked == false))
  {
    alert ('Please tell us if your caravan has a Motor Mover fitted.');
    return false;
  }
  else if (document.getElementById('caravanTitle').value == "")
  {
    alert ('Please enter your title.');
    document.getElementById('caravanTitle').focus();
    return false;
  }
  else if (document.getElementById('caravanForename').value == "")
  {
    alert ('Please enter your forename.');
    document.getElementById('caravanForename').focus();
    return false;
  }
  else if (document.getElementById('caravanSurname').value == "")
  {
    alert ('Please enter your surname.');
    document.getElementById('caravanSurname').focus();
    return false;
  }
  else if (document.getElementById('caravanCounty').value == "")
  {
    alert ('Please enter your county.');
    document.getElementById('caravanCounty').focus();
    return false;
  }
  else if (document.getElementById('caravanPhone').value == "")
  {
    alert ('Please enter your phone number.');
    document.getElementById('caravanPhone').focus();
    return false;
  }
  else if (document.getElementById('caravanEmail').value == "")
  {
    alert ('Please enter your Email.');
    document.getElementById('caravanEmail').focus();
    return false;
  }
  else if (checkEmailAddress(document.getElementById('caravanEmail').value) == false)
    {
      alert ('Please enter a valid Email address.');
	  document.getElementById('caravanEmail').focus();
      return false;
	}
  else
  {
    return true;	  
  }
}

function checkSellMotorhomeForm()
{
  if (document.getElementById('motorhomeMake').value == "")
  {
    alert ('Please enter the motorhome make.');
    document.getElementById('motorhomeMake').focus();
    return false;
  }
  else if (document.getElementById('motorhomeModel').value == "")
  {
    alert ('Please enter the motorhome model.');
    document.getElementById('motorhomeModel').focus();
    return false;
  }
  else if (document.getElementById('motorhomeYear').value == "")
  {
    alert ('Please enter the year.');
    document.getElementById('motorhomeYear').focus();
    return false;
  }
  else if (document.getElementById('motorhomeCC').value == "")
  {
    alert ('Please enter the engine CC.');
    document.getElementById('motorhomeCC').focus();
    return false;
  }
  else if ((document.getElementById('motorhomePetrol').checked == false) &&
			(document.getElementById('motorhomeDiesel').checked == false) &&
			(document.getElementById('motorhomeTurboDiesel').checked == false))
  {
    alert ('Please tell us your motorhome\'s engine type.');
    return false;
  }
  else if ((document.getElementById('motorhomeManual').checked == false) &&
			(document.getElementById('motorhomeAutomatic').checked == false))
  {
    alert ('Please tell us your motorhome\'s transmission type.');
    return false;
  }
  else if (document.getElementById('motorhomeMileage').value == "")
  {
    alert ('Please enter your motorhome\s mileage.');
    document.getElementById('motorhomeMileage').focus();
    return false;
  }
  else if ((document.getElementById('motorhomeMotYes').checked == false) &&
			(document.getElementById('motorhomeMotNo').checked == false))
  {
    alert ('Please tell us whether your motorhome has an MOT certificate.');
    return false;
  }
  else if ((document.getElementById('motorhomeMotYes').checked == true) && (document.getElementById('motorhomeMotMonths').value == ""))
  {
    alert ('Please tell us how many months are left on your Motorhome\'s MOT.');
    document.getElementById('motorhomeMotMonths').focus();
    return false;
  }
  else if ((document.getElementById('motorhomeRflYes').checked == false) &&
			(document.getElementById('motorhomeRflNo').checked == false))
  {
    alert ('Please tell us whether your motorhome is currently taxed.');
    return false;
  }
  else if ((document.getElementById('motorhomeRflYes').checked == true) && (document.getElementById('motorhomeRflMonths').value == ""))
  {
    alert ('Please tell us how many months are left on your Motorhome\'s road tax.');
    document.getElementById('motorhomeRflMonths').focus();
    return false;
  }
  else if ((document.getElementById('motorhomeFshYes').checked == false) &&
			(document.getElementById('motorhomeFshNo').checked == false))
  {
    alert ('Please tell us whether your motorhome has a full service history.');
    return false;
  }
  else if ((document.getElementById('motorhomeCanopyYes').checked == false) &&
			(document.getElementById('motorhomeCanopyNo').checked == false))
  {
    alert ('Please tell us whether your motorhome has a rollout canopy.');
    return false;
  }
  else if ((document.getElementById('motorhomeCycleRackYes').checked == false) &&
			(document.getElementById('motorhomeCycleRackNo').checked == false))
  {
    alert ('Please tell us whether your motorhome has a cycle rack.');
    return false;
  }
  else if ((document.getElementById('motorhomeAirConYes').checked == false) &&
			(document.getElementById('motorhomeAirConNo').checked == false))
  {
    alert ('Please tell us whether your motorhome has air conditioning.');
    return false;
  }
  else if ((document.getElementById('motorhomeV5Yes').checked == false) &&
			(document.getElementById('motorhomeV5No').checked == false))
  {
    alert ('Please tell us whether the V5 document is in your name.');
    return false;
  }
  else if ((document.getElementById('motorhomeInteriorPoor').checked == false) &&
			(document.getElementById('motorhomeInteriorAverage').checked == false) &&
			(document.getElementById('motorhomeInteriorGood').checked == false) &&
			(document.getElementById('motorhomeInteriorExcellent').checked == false))
  {
    alert ('Please tell us the condition of your motorhome\'s interior.');
    return false;
  }
  else if ((document.getElementById('motorhomeExteriorPoor').checked == false) &&
			(document.getElementById('motorhomeExteriorAverage').checked == false) &&
			(document.getElementById('motorhomeExteriorGood').checked == false) &&
			(document.getElementById('motorhomeExteriorExcellent').checked == false))
  {
    alert ('Please tell us the condition of your motorhome\'s exterior.');
    return false;
  }

  else if (document.getElementById('motorhomeTitle').value == "")
  {
    alert ('Please enter your title.');
    document.getElementById('motorhomeTitle').focus();
    return false;
  }
  else if (document.getElementById('motorhomeForename').value == "")
  {
    alert ('Please enter your forename.');
    document.getElementById('motorhomeForename').focus();
    return false;
  }
  else if (document.getElementById('motorhomeSurname').value == "")
  {
    alert ('Please enter your surname.');
    document.getElementById('motorhomeSurname').focus();
    return false;
  }
  else if (document.getElementById('motorhomeCounty').value == "")
  {
    alert ('Please enter your county.');
    document.getElementById('motorhomeCounty').focus();
    return false;
  }
  else if (document.getElementById('motorhomePhone').value == "")
  {
    alert ('Please enter your phone number.');
    document.getElementById('motorhomePhone').focus();
    return false;
  }
  else if (document.getElementById('motorhomeEmail').value == "")
  {
    alert ('Please enter your Email.');
    document.getElementById('motorhomeEmail').focus();
    return false;
  }
  else if (checkEmailAddress(document.getElementById('motorhomeEmail').value) == false)
    {
      alert ('Please enter a valid Email address.');
	  document.getElementById('motorhomeEmail').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);
}