/**
 *	validate a email address
 */
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;
}

/**
 *	required field
 */
function validRequired(formField,fieldLabel)
{
	var result = true;
	
	if (formField.value == "")
	{
		alert('Bitte geben Sie einen Wert für das Feld "' + fieldLabel +'" ein.');
		formField.focus();
		result = false;
	}
	
	return result;
}

/**
 *	only chars
 */
function allDigits(str)
{
	return inValidCharSet(str,"0123456789");
}

/**
 *	given charset
 */
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;
}

/**
 *	valid email
 */
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("Bitte geben Sie eine richtige eMail ein in der Form: email@domain.de");
		formField.focus();
		result = false;
	}
	
	return result;
}

/**
 *	valid numbers only
 */
function validNum(formField,fieldLabel,required)
{
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;

 	if (result)
 	{
 		if (!allDigits(formField.value))
 		{
 			alert('Bitte geben Sie eine Zahl in das Feld "' + fieldLabel +'" ein.');
			formField.focus();		
			result = false;
		}
	} 

	return result;
}

/**
 *	valid integer
 */
function validInt(formField,fieldLabel,required)
{
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;

 	if (result)
 	{
 		var num = parseInt(formField.value,10);
 		if (isNaN(num))
 		{
 			alert('Bitte geben Sie eine Zahl in das Feld "' + fieldLabel +'" ein.');
			formField.focus();		
			result = false;
		}
	} 

	return result;
}

/**
 *	valid date
 */
function validDate(formField,fieldLabel,required)
{
	//	format: YYYY-MM-DD
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;

 	if (result)
 	{
 		var elems = formField.value.split("-");
 		
 		result = (elems.length == 3); // should be three components
 		
 		if (result)
 		{
 			var year = parseInt(elems[0],10);
 			var month = parseInt(elems[1],10);
  			var day = parseInt(elems[2],10);
			result = allDigits(elems[0]) && (month > 0) && (month < 13) &&
					 allDigits(elems[1]) && (day > 0) && (day < 32) &&
					 allDigits(elems[2]) && ((elems[2].length == 2) || (elems[2].length == 4));
 		}
 		
  		if (!result)
 		{
 			alert('Bitte geben Sie ein Datum in der Form JJJJ-MM-TT in das Feld "' + fieldLabel +'" ein.');
			formField.focus();		
		}
	}

	return result;
}