// Check email form is in correct format
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;
}


// Ensure a value is entered in required fields
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;
}

// Ensure a value is selected from dropdown lists
// Same as validRequired
// Just text output changed
function validRequired2(formField,fieldLabel)
{
	var result = true;
	
	if (formField.value == "")
	{
		alert('Please select a value for the ' + fieldLabel +' from the dropdown list.');
		formField.focus();
		result = false;
	}
	
	return result;
}

// Set valid characters to be numbers
function allDigits(str)
{
	return inValidCharSet(str,"0123456789");
}


// Check string to ensure no invalid characters
function inValidCharSet(str,charset)
{
	var result = true;

	for (var i=0;i<str.length;i++)
		if (charset.indexOf(str.substr(i,1))<0)
		{
			result = false;
			break;
		}
	
	return result;
}

// Check validity of email address against isEmailAddr function
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 valid email address in the form: yourname@yourdomain.com");
		formField.focus();
		result = false;
	}
   
  return result;

}

// Check value entered is a number
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;
}