How to validate email in Jquery?

Change your input.email block as this:

            if (email == '') {
            $('input.email').addClass('error');
            $('input.email').keypress(function(){
                $('input.email').removeClass('error');
            });
            $('input.email').focusout(function(){
                $('input.email').filter(function(){
                    return this.value.match(/your email regex/);
                }).addClass('error');
            });
        }

Explaination: Add focusout action to input.email form element, validates the email string using RFC822 standard. If it can't pass then add the 'error' class.

I have not tested this on my browser but it should work for jQuery > 1.4.

EDIT: I've removed the regex, place your favorite one there.

If you really don't want to use a plugin I've found this method to be quite good:

function validateEmail(email) {
    var emailReg = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;
    if( !emailReg.test( email ) ) {
        return false;
    } else {
        return true;
    }
}

JSFIDDLE

http://thejimgaudet.com/articles/support/web/jquery-e-mail-validation-without-a-plugin/

I'm currently using ketchup for form validation. There's also bassassist's plugin. Check a plugin, it will save you hours of regex-writing code.

You can use RegEx if you don't want to use any plugins.

var testEmail = /^[A-Z0-9._%+-]+@([A-Z0-9-]+\.)+[A-Z]{2,4}$/i;
if (testEmail.test(valueToTest))
    // Do whatever if it passes.
else
    // Do whatever if it fails.

This will get you most emails. An interesting read about validating emails with RegEx.

You can test the script here: http://jsfiddle.net/EFfCa/