function EmailCheck(emailStr)
{
  var emailPat=/^(.+)@(.+)$/
  var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"
  var validChars="\[^\\s" + specialChars + "\]"
  var firstChars=validChars
  var quotedUser="(\"[^\"]*\")"
  var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/
  var atom="(" + firstChars + validChars + "*" + ")"
  var word="(" + atom + "|" + quotedUser + ")"
  var userPat=new RegExp("^" + word + "(\\." + word + ")*$")
  var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
  var matchArray=emailStr.match(emailPat)
  if (matchArray==null) 
  {
  
    alert("Alamat email belum diisi atau salah dalam penulisannya!");
    return false;
  }
  var user=matchArray[1]
  var domain=matchArray[2]

  if (user.match(userPat)==null) {
    alert("Alamat email Anda salah");
    return false;
  }

  var IPArray=domain.match(ipDomainPat)
  if (IPArray!=null) {
    for (var i=1;i<=4;i++) {
      if (IPArray[i]>255) {
	alert("Alamat tujuan IP address nya salah!");
	return false;
      }
    }
    return true;
  }

  var domainArray=domain.match(domainPat)
  if (domainArray==null) {
    alert("Alamat email Anda untuk domain salah");
    return false;
  }
  var atomPat=new RegExp(atom,"g")
  var domArr=domain.match(atomPat)
  var len=domArr.length
  if (domArr[domArr.length-1].length<2 || domArr[domArr.length-1].length>3) {
    alert("Alamat email Anda harus berakhiran 3 karakter domain atau 2 karakter kode negara");
    return false;
  }

  if (domArr[domArr.length-1].length==2 && len<3) {
     var errStr="Alamat email Anda salah"
     alert(errStr);
     return false;
  }

  if (domArr[domArr.length-1].length==3 && len<2) {
     var errStr="Alamat email Anda salah"
     alert(errStr);
     return false
  }
  return true;
}