I wish to install a widget on my website for seeking the eMail ID of all visiting traffic for future communication.
If by 'record' you refer to capture user's email address without his or her consent than it's very unlikely. It violates users' privacy and might be considered illegal.
That being said, there are some less aggressive ways to get subscribers/emails. Here on MakeUseOf we use Aweber that integrates a form to the website where users may enter their email account and get subscribed to our newsletter.