function CheckEmail(emailStr) {
var checkTLD=1;
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
var emailPat=/^(.+)@(.+)$/;
var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
var validChars="\[^\\s" + specialChars + "\]";
var quotedUser="(\"[^\"]*\")";
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
var atom=validChars + '+';
var word="(" + atom + "|" + quotedUser + ")";
var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
var matchArray=emailStr.match(emailPat);

  if (matchArray==null) {
    alert("Dia chi e-mail khong chinh xac!");
    return false;
  }

var user=matchArray[1];
var domain=matchArray[2];

  for (i=0; i<user.length; i++) {
    if (user.charCodeAt(i)>127) {
      alert("Ten nguoi dung cua dia chi e-mail chua ky tu khong hop le!");
      return false;
    }
  }
  for (i=0; i<domain.length; i++) {
    if (domain.charCodeAt(i)>127) {
      alert("Ten domain cua dia chi e-mail chua ky tu khong hop le!");
      return false;
    }
  }

  if (user.match(userPat)==null) {
    alert("Ten nguoi dung cua dia chi e-mail khong hop le!");
    return false;
  }

var IPArray=domain.match(ipDomainPat);

  if (IPArray!=null) {
    for (var i=1;i<=4;i++) {
      if (IPArray[i]>255) {
        alert("Dia chi IP dich cua dia chi e-mail khong hop le!");
        return false;
      }
    }
    return true;
  }

var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;

  for (i=0;i<len;i++) {
    if (domArr[i].search(atomPat)==-1) {
      alert("Ten domain cua dia chi e-mail khong hop le!");
      return false;
    }
  }

  if (checkTLD && domArr[domArr.length-1].length!=2 &&
     domArr[domArr.length-1].search(knownDomsPat)==-1) {
    alert("Dia chi e-mail phai ket thuc voi domain da biet hoac voi hai ky tu cua ten nuoc!");
    return false;
  }

  if (len<2) {
    alert("Dia chi e-mail khong co hostname!");
    return false;
  }

  return true;
}
function CheckEmail_en(emailStr) {
var checkTLD=1;
var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
var emailPat=/^(.+)@(.+)$/;
var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
var validChars="\[^\\s" + specialChars + "\]";
var quotedUser="(\"[^\"]*\")";
var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
var atom=validChars + '+';
var word="(" + atom + "|" + quotedUser + ")";
var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
var matchArray=emailStr.match(emailPat);

  if (matchArray==null) {
        alert("Email is incorect. Please enter again!");
    return false;
  }

var user=matchArray[1];
var domain=matchArray[2];

  for (i=0; i<user.length; i++) {
    if (user.charCodeAt(i)>127) {
      //alert("Ten nguoi dung cua dia chi e-mail chua ky tu khong hop le!");
        alert("Email is incorect. Please enter again!");
      return false;
    }
  }
  for (i=0; i<domain.length; i++) {
    if (domain.charCodeAt(i)>127) {
      //alert("Ten domain cua dia chi e-mail chua ky tu khong hop le!");
        alert("Email is incorect. Please try again!");
      return false;
    }
  }

  if (user.match(userPat)==null) {
//    alert("Ten nguoi dung cua dia chi e-mail khong hop le!");
        alert("Email is incorect. Please enter again!");
    return false;
  }

var IPArray=domain.match(ipDomainPat);

  if (IPArray!=null) {
    for (var i=1;i<=4;i++) {
      if (IPArray[i]>255) {
//        alert("Dia chi IP dich cua dia chi e-mail khong hop le!");
        alert("Email is incorect. Please enter again!");
        return false;
      }
    }
    return true;
  }

var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;

  for (i=0;i<len;i++) {
    if (domArr[i].search(atomPat)==-1) {
//      alert("Ten domain cua dia chi e-mail khong hop le!");
    alert("Email is incorect. Please enter again!");
      return false;
    }
  }

  if (checkTLD && domArr[domArr.length-1].length!=2 &&
     domArr[domArr.length-1].search(knownDomsPat)==-1) {
    alert("Dia chi e-mail phai ket thuc voi domain da biet hoac voi hai ky tu cua ten nuoc!");
    return false;
  }

  if (len<2) {
    alert("Dia chi e-mail khong co hostname!");
    return false;
  }

  return true;
}


function check_form(){
	var ht=lh.ht.value;
	var cty=lh.cty.value;
	var dc=lh.dc.value;
	var tel=lh.dt.value;
	var email=lh.email.value;
	var contents=lh.nd.value;

	if(ht==""){ alert("Please input your full name!"); return;}
	if(email==""){ alert("Please input your email address!"); return;}
	if(contents==""){ alert("Please input your messages!"); return;}
	if(CheckEmail(email)){ lh.submit(); } 
}
//check email
function isemail(email)
{
  var result = false;
  var theStr = new String(email);
  var index = theStr.indexOf("@");
  if (index > 0)
  {
    var pindex = theStr.indexOf(".",index);
    if ((pindex > index+1) && (theStr.length > pindex+1))
	result = true;
  }
  return result;
}

function lienhe()
{
	var ht = document.lh.hoten.value;
	var email = document.lh.email.value;
	var nd = document.lh.noidung.value;
	 
    if(ht=="")
	{
		alert("Vui long nhap ho ten!");
		lh.hoten.focus();
 		return;
	}
	if(nd=="")
	{	alert("Vui long nhap yeu cau cua ban!");
		lh.noidung.focus();
 		return;
	}
	if(CheckEmail(email))
	{
		mail_err = 0;

	}
	
	else
	{
		mail_err = 1;
		document.lh.email.focus();
		return;
	}
	if(!mail_err)
	{
		document.lh.submit();
	}
}
function contact()
{
	var ht = document.lh.hoten.value;
	var email = document.lh.email.value;
	var nd = document.lh.noidung.value;
	 
    if(ht=="")
	{
		alert("Please enter your full name!");
		lh.hoten.focus();
 		return;
	}
	if(nd=="")
	{	alert("Please enter your comment!");
		lh.noidung.focus();
 		return;
	}
	if(CheckEmail_en(email))
	{
		mail_err = 0;

	}
	
	else
	{
		mail_err = 1;
		document.lh.email.focus();
		return;
	}
	if(!mail_err)
	{
		document.lh.submit();
	}
}
//-->

function huy()
{	document.lh.reset();
}