function isEmailAddress (string) {
  var addressPattern = 
    /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
  return addressPattern.test(string);
}


function isTel (string) {
  var addressPattern = 
  /^(((\+|[0]{2})\d{2})|[0])((\d{2}(-|\s)[1-9]\d{6})|(\d{3}(-|\s)[1-9]\d{5})|(\d{9}))\d*/;
  return addressPattern.test(string);
}

function isNum (string) {
  var addressPattern =  /^\d+$/;
  return addressPattern.test(string);
}

function isMobile (string) {
  var addressPattern = 
    /^(((\+|[0]{2})\d{2})|[0])6(-{0,1})[1-9][0-9]{7}$/;
  return addressPattern.test(string);
}

function isTijd (string) {
  var addressPattern = 
     /^([01]?[0-9]|[2][0-3]):[0-5][0-9]$/;
  return addressPattern.test(string);
}

function isPostcode (obj) {
  string = obj.value;
  var addressPattern = /^\d{4}\s[A-Za-z]{2}$/;
  if(addressPattern.test(string)){
	return true;
  }
  addressPattern = /^\d{4}[A-Za-z]{2}$/;
  if(addressPattern.test(string)){
	obj.value = string.substr(0,4) + ' ' + string.substr(4,2);
	return true;
  }
  return false;
}
function trim(s) {
  while (s.substring(0,1) == ' ') {
    s = s.substring(1,s.length);
  }
  while (s.substring(s.length-1,s.length) == ' ') {
    s = s.substring(0,s.length-1);
  }
  return s;
}