function isNull(str)
{
  var re = /.+/;
  
  str = str.replace(/^\s+|\s+$/g, '');
  if (re.test(str)) {
	return false;
  } 
  return true;
}

function isEmail(str) {
  var re = /^[\w-]+(?:\.[\w-]+)*@(?:[\w-]+\.)+[a-zA-Z]{2,7}$/;
  if (re.test(str)) {
    return true;
  }
  return false;
}

function checkContactFrm(formObj)
{
	if (isNull(formObj.llname.value)) {
		alert ("Please input your name.");
	} else if (isNull(formObj.email.value) || !isEmail(formObj.email.value)) {
		alert ("Email format is not correct. ");
	} else if (isNull(formObj.subject.value)) {
		alert ("Please input subject.");
	} else if (isNull(formObj.message.value)) {
		alert ("Please input content.");
	} else {
		return true;
	}
	return false;
}