function isValidEmail(mail)
{
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(mail))
	{
		return true;
	}
	else
	{
		return false;
	}
}

function doReg(form)
{
	if(!isValidEmail(form.email.value))
	{
		alert("Please use a correct email.")
		form.email.focus();
		return false;
	}
	else
	{
		form.action=form.action + 'regrequest';
		form.submit();
	}
}
function doUnreg(form)
{
	if(!isValidEmail(form.email.value))
	{
		alert("Please use a correct email.")
		form.mail.focus();
		return false;
	}
	else
	{
		form.action=form.action + 'unregrequest';
		form.submit();
	}
}