function ChkEmail(form,txt_mail) {
 if (txt_mail !=""){
	if ((txt_mail.indexOf("<") !=-1) ||
		(txt_mail.indexOf(">") !=-1) ||
		(txt_mail.indexOf("(") !=-1) ||
		(txt_mail.indexOf(")") !=-1) ||
		(txt_mail.indexOf(",") !=-1) ||
		(txt_mail.indexOf("!") !=-1) ||
		(txt_mail.indexOf("'") !=-1) ||
		(txt_mail.indexOf(":") !=-1) ||
		(txt_mail.indexOf('"') !=-1) ||
		(txt_mail.indexOf("\\") !=-1) ||
		(txt_mail.indexOf("#") !=-1) ||
		(txt_mail.indexOf("[") !=-1) ||
		(txt_mail.indexOf("]") !=-1) ||
		(txt_mail.indexOf(";") !=-1) ||
		(txt_mail.indexOf("%") !=-1) ||
		(txt_mail.indexOf("@")==-1) ||
		(txt_mail.slice(txt_mail.indexOf("@")+1, txt_mail.length) == "") ||
		(txt_mail.slice(txt_mail.indexOf("@")+1, txt_mail.length).indexOf(".") == -1) ||
		(txt_mail.charAt(txt_mail.length - 1) == "." ) ||
		(txt_mail.slice(txt_mail.slice(txt_mail.indexOf("@")+1, txt_mail.length).indexOf(".")) == ""))
		{ 
			alert("The email address invalid. Please make sure it is in a correct format\ne.g. yourname@domain.com");
	return true;
	}	
	}
}

function ChkRequireField(form) 
{
	if (form.RName.value=="")
	{
		alert("Ban chua nhap ten");
		form.RName.focus();
		return false;
	}
	else if (form.REmail.value==""){
		alert("Ban chua nhap Email");
		form.REmail.focus();
		return false;
	}
	else if (form.RMess.value==""){
		alert("Ban chua nhap Email");
		form.REmail.focus();
		return false;
	}

	return true;
}