function isEmailAddr(email)
{
  var result = false;
  var theStr = new String(email);
  var index = theStr.indexOf("@");
  if (index > 0)
  {
    var pindex = theStr.indexOf(".",index);
    if ((pindex > index+1) && (theStr.length > pindex+1))
	result = true;
  }
  return result;
}

function validRequired(formField,fieldLabel)
{
	var result = true;
	if (formField.value == "")
	{
		alert('Please enter a value for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	return result;
}

function validRequiredTickbox(formField,fieldLabel)
{
	var result = true;
	if (formField.checked != true)
	{
		alert('You must tick the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	return result;
}

function selectRequired(formField,fieldLabel)
{
	var result = true;
	if (formField.selectedIndex  == "0")
	{
		alert('Please select an option for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	return result;
}

function allDigits(str)
{
	return inValidCharSet(str,"0123456789");
}

function allDigitsPlus(str)
{
	return inValidCharSet(str,"0123456789.");
}

function allAlpha(str)
{
	return inValidCharSet(str,"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_@");
}

function alphanumeric(formField,fieldLabel)
{
	var result = true;
 		if (!allAlpha(formField.value))
 		{
 			alert('Please enter a value for the "' + fieldLabel +'" field using only numbers, letters, and (-), (_), (@) or (.)');
			formField.focus();		
			result = false;
		}
	return result;
}

function inValidCharSet(str,charset)
{
	var result = true;
	// Note: doesn't use regular expressions to avoid early Mac browser bugs	
	for (var i=0;i<str.length;i++)
		if (charset.indexOf(str.substr(i,1))<0)
		{
			result = false;
			break;
		}
	return result;
}

function validEmail(formField,fieldLabel,required)
{
	var result = true;
	if (required && !validRequired(formField,fieldLabel))
		result = false;
	if (result && ((formField.value.length < 3) || !isEmailAddr(formField.value)) )
	{
		alert('Please enter a complete email address in the form: yourname@yourdomain.com for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
  return result;
}

function validNum(formField,fieldLabel,required)
{
	var result = true;
	if (required && !validRequired(formField,fieldLabel))
		result = false;
 	if (result)
 	{
 		if (!allDigits(formField.value))
 		{
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	return result;
}

function validDecimal(formField,fieldLabel,required)
{
	var result = true;
	if (required && !validRequired(formField,fieldLabel))
		result = false;
 	if (result)
 	{
 		if (!allDigitsPlus(formField.value))
 		{
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	return result;
}

function validInt(formField,fieldLabel,required)
{
	var result = true;
	if (required && !validRequired(formField,fieldLabel))
		result = false;
 	if (result)
 	{
 		var num = parseInt(formField.value);
 		if (isNaN(num))
 		{
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	return result;
}

function validMatch(formField1,fieldLabel1,formField2,fieldLabel2)
{
	var result = true;
	if (formField1.value != formField2.value)
	{
		alert('The field "' + fieldLabel1 + '" must match the field "' + fieldLabel2 +'".');
		formField1.focus();		
		result = false;
	}
	return result;
}
function validDependent(formField1,fieldLabel1,formField2,fieldLabel2)
{
	var result = true;
	if (formField1.checked == true && formField2.value == "0")
	{
		alert('You have ticked the field "' + fieldLabel1 + '" and so must select an option from the field "' + fieldLabel2 +'".');
		formField2.focus();		
		result = false;
	}
	return result;
}