function EmailCheck (emailFld) {
emailStr=emailFld.value;
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 +")*$");
var matchArray=emailStr.match(emailPat);
if (matchArray==null) {
	if (emailStr=="") {
		return true;
	} else {
		alert("Direccion de email no valida.");
		document.frmmailer.txtfrome.focus()
		return 0;
	}
}
var user=matchArray[1];
var domain=matchArray[2];
for (i=0; i<user.length; i++) {
	if (user.charCodeAt(i)>127) {
		alert("Caracteres Invalidos");
		return false;
	}
}
for (i=0; i<domain.length; i++) {
	if (domain.charCodeAt(i)>127) {
		alert("Caracteres invalidos");
		return false;
	}
}
if (user.match(userPat)==null) {
	alert("Parece un email no valido");
	return false;
}
var IPArray=domain.match(ipDomainPat);
if (IPArray!=null) {
	for (var i=1;i<=4;i++) {
		if (IPArray[i]>255) {
			alert("IP doesn't look right");
			return false;
		}
	}
	return true;
}
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;
for (i=0;i<len;i++) {
	if (domArr[i].search(atomPat)==-1) {
		alert("Dominio del email parece no valido");
		return false;
	 }
}
if (checkTLD && domArr[domArr.length-1].length!=2 && domArr[domArr.length-1].search(knownDomsPat)==-1) {
	alert("Unknown domain termination");
	return false;
}
if (len<2) {
	alert("Dominio no funciona");
	return false;
}
return true;
}