function $(id) {
  return document.getElementById(id);
}
function isBlank(fieldValue) {
	var blankSpaces = / /g;
	fieldValue = fieldValue.replace(blankSpaces, "");
	return (fieldValue == "") ? true : false;
}

function isEmailValid(fieldValue) {
	var emailFilter = /^.+@.+\..{2,4}$/;
	var atSignFound = 0;
	for (var i = 0; i <= fieldValue.length; i++)
		if ( fieldValue.charAt(i) == "@" )
			atSignFound++;
	if ( atSignFound > 1 )
		return false;
	else
		return ( emailFilter.test(fieldValue) && !doesEmailHaveInvalidChar(fieldValue) ) ? true : false;
}

function doesEmailHaveInvalidChar(fieldValue) {
	var illegalChars = /[\(\)\<\>\,\;\:\\\/\"\[\] ]/;
	return ( illegalChars.test(fieldValue) ) ? true : false;
}

function sprawdz_email() {
  var email = $("email").value;
  if (isBlank(email) || !isEmailValid(email) ) {
				  alert('podany adres email: ' + email + ' jest bledny');
				  return false;
  }
  else {
		document.formularz.submit();
	}
}