function is_email(address) {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   if(reg.test(address) == false) {
      return false;
   }
   
   return true;
}

function is_password(password)
{
	var reg = /[^A-Za-z0-9]/;
	//alert(reg.test(password));
	if(reg.test(password) == true) {
      return false;
   }
   
   return true;
}

function is_username(username)
{
	
	var reg = /[^A-Za-z0-9_\-\.]/;

	if(reg.test(username) == true) {
      return false;
   }
   return true;
}