/**************************************************************
IsEmail: Returns a Boolean if the specified Expression is a
          valid e-mail address. If Expression is null, false
          is returned.

Parameters:
      Expression = e-mail to validate.

Returns: Boolean
***************************************************************/
function IsEmail(Expression)
{
	if (Expression == null)
		return (false);

	var supported = 0;
	if (window.RegExp)
	{
		var tempStr = "a";
		var tempReg = new RegExp(tempStr);
		if (tempReg.test(tempStr)) supported = 1;
	}
	if (!supported)
		return (Expression.indexOf(".") > 2) && (Expression.indexOf("@") > 0);
	var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
	var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
	return (!r1.test(Expression) && r2.test(Expression));
}


function Mid(String, Start, Length)
{
	if (String == null)
		return (false);

	if (Start > String.length)
		return '';

	if (Length == null || Length.length == 0)
		return (false);

	return String.substr((Start - 1), Length);
}

function InStr(String1, String2)
{
	var a = 0;

	if (String1 == null || String2 == null)
		return (false);

	String1 = String1.toLowerCase();
	String2 = String2.toLowerCase();

	a = String1.indexOf(String2);
	if (a == -1)
		return 0;
	else
		return a + 1;
}

function LTrim(String)
{
	var i = 0;
	var j = String.length - 1;

	if (String == null)
		return (false);

	for (i = 0; i < String.length; i++)
	{
		if (String.substr(i, 1) != ' ' && String.substr(i, 1) != '\t')
			break;
	}

	if (i <= j)
		return (String.substr(i, (j+1)-i));
	else
		return ('');
}

function RTrim(String)
{
	var i = 0;
	var j = String.length - 1;

	if (String == null)
		return (false);

	for(j = String.length - 1; j >= 0; j--)
	{
		if (String.substr(j, 1) != ' ' && String.substr(j, 1) != '\t')
		break;
	}

	if (i <= j)
		return (String.substr(i, (j+1)-i));
	else
		return ('');
}

function Trim(String)
{
	if (String == null)
		return (false);

	return RTrim(LTrim(String));
}

function IsNumber(Expression)
{
	Expression = Expression.toLowerCase();
	RefString = "0123456789.-";

	if (Expression.length < 1) 
		return (false);

	for (var i = 0; i < Expression.length; i++) 
	{
		var ch = Expression.substr(i, 1)
		var a = RefString.indexOf(ch, 0)
		if (a == -1)
			return (false);
	}
	return(true);
}