function isEmailFormat(emailStr) {
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 MsgErr="";   
var matchArray=emailStr.match(emailPat)
if (matchArray==null) {
	MsgErr=MsgErr+"Email address seems incorrect (check @ and .'s) ";
	return MsgErr;
}
else
{
  var user=matchArray[1]
  var domain=matchArray[2]
  if (user.match(userPat)==null) {
    MsgErr=MsgErr+"The username doesn't seem to be valid. ";
	return MsgErr;
   }
  var IPArray=domain.match(ipDomainPat)
   if (IPArray!=null) {
	  for (var i=1;i<=4;i++) {
	    if (IPArray[i]>255) {
	        MsgErr=MsgErr+"Destination IP address is invalid ! ";
			return MsgErr;
	     }//IF
		}//for
     }//IP Array
   var domainArray=domain.match(domainPat)
   if (domainArray==null) {
	 MsgErr=MsgErr+"The domain name doesn't seem to be valid.";
	 return MsgErr;
     }
    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) {
     MsgErr=MsgErr+"The address must end in a three-letter domain, or two letter country.";
	 return MsgErr;
    }
   if (len<2) {
     MsgErr=MsgErr+"This address is missing a hostname!";
	 return MsgErr;
   } 
 }//End  Match
return "0";
}