This error I came across while making an ajax call using jquery ajax function. After a long analysis I was able to figure it out, so thought of sharing with everyone.
When you reference the jQuery on your web page, you have to specify the version number also. There is also a way to always load the latest jQuery library file from google CDN. Here is one such example.
For email address validation there is Official Standard: RFC 5322 but the regex to match this standard is very complex and would not be suitable for implementation in our applications, but the below regex is the most appropriate to be used in our applications. I didn’t find a bug till now.