jQuery Validation Email Validation Issues

I am trying to troubleshoot and fix why my email validation is not properly working. It is suppose to detect an invalid email: where it had too many ...(dots), to still except European address (test@tom.uk.tk) as well as test@aol.com. But as of right now its excepting more that one dot, if you don't finish typing as long as it has the @ as long as you don't add the (.) dot. Will someone please help me with where I am going wrong?

<script>
     $("#form").validate({
    rules: {
        firstname_1: {
            required: true
        },
        email_1: {
            required: true,
            email: true
        },
        // Same for other fields
    },
    messages: {
        firstname_1: "This field is required.",
        email_1>: "Please enter valid email address.",
        // Repeat for other fields
    }
});
function isValidEmail(email_1)
{
    return /^[a-z0-9]+([-._][a-z0-9]+)*@([a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,4}$/.test(email_1)
        && /^(?=.{1,64}@.{4,64}$)(?=.{6,100}$).*/.test(email_1);
}
</script>

Assuming you already have the correct validation logic and/or regex, then you would need to create your own rule using the .addMethod() method.

$("#form").validate({
    rules: {
        firstname_1: {
            required: true
        },
        email_1: {
            required: true,
            myEmail: true  // <- declare your custom rule
        },
        // Same for other fields
    },
    messages: {
        firstname_1: "This field is required.",
        email_1: "Please enter valid email address.",
        // Repeat for other fields
    }
});

// create your custom rule
jQuery.validator.addMethod("myEmail", function(value, element) {
    return this.optional(element) || /* your regex boolean logic goes here */;
}, 'Please enter valid email address.');

NOTE: You also had a syntax/spelling error on a field name within messages. Should be email_1, not email_1>.

See this answer for the proper way to use .addMethod().