function trim(s) {
// trim leading and trailing "whitespace"
var whitespace = " \t\n\r";
var i = 0;
while ((i < s.length) && (whitespace.indexOf(s.charAt(i)) != -1)) i++;
var j = s.length;
while ((j > i) && (whitespace.indexOf(s.charAt(j-1)) != -1)) j--;
return s.substr(i,j - i);
}
function isEmailValid(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 matchArray=emailStr.match(emailPat);
if (matchArray==null) return false;
var user=matchArray[1]
var domain=matchArray[2]
if (user.match(userPat)==null) return false;
var IPArray=domain.match(ipDomainPat)
if (IPArray!=null) {
for (var i=1;i<=4;i++) {
if (IPArray[i]>255) return false;
}
return true;
}
var domainArray=domain.match(domainPat)
if (domainArray==null) 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>4) return false;
if (len<2) return false;
return true;
}