function validate_required(field,alerttxt,defaultValue)
{
	with (field)
	{
		if ((value == null) || (value == "") || (value == defaultValue))
		{ alert(alerttxt); return false; }
		else return true;
	}
}

function validate_email(field,alerttxt)
{
	with (field)
	{
		apos = value.indexOf("@");
		dotpos = value.lastIndexOf(".");
		if ( apos < 1 ) 
		{ alert(alerttxt); return false; }
		else if ( (dotpos - apos) < 2 ) 
		{ alert(alerttxt); return false; }
		else return true;
	}
}

function validate_form(thisform)
{
	with (thisform)
	{
		if (validate_required(email,"Please supply your email address.","EMAIL ADDRESS") == false)
			{email.focus(); return false;}
		if (validate_email(email,"The email address you supplied doesn't appear to be valid. Please supply a valid email address.") == false)
			{email.focus(); return false;}
		if (validate_required(zipcode,"Please supply your zipcode.","POSTAL CODE") == false)
			{zipcode.focus(); return false;}
	}
}