valid-email.js

    Backbone.validEmail = function(emailAddress){
        //var pattern = new RegExp(/^\w[-._\w]*\w(\+\w+)?@\w[-._\w]*\w\.\w{2,6}$/i);
        //var pattern = new RegExp(/^\w([-._+\w]*\w)?@\w[-._\w]*\w\.\w{2,6}$/i);
        //var pattern = new RegExp(/^\w([-.+\w]*\w)?@\w[-.\w]*\w\.\w{2,12}$/i);
        //var pattern = new RegExp(/^\w([-._+\w]*\w)?@\w([-._+\w]*\w)?\.\w{2,12}$/i);


        var pattern = new RegExp(/^\w([-._+\w]*\w)?@\w([-._+\w]*\w)?\.\w{2,12}$/i);

        var go=pattern.test(emailAddress);
        if(emailAddress.length < 6 || emailAddress.length > 254)go=false;

        return go;
    };