$(document).ready(function() {
    $("#login_form_top").live('mouseover', function(){
        $(this).validate({
            rules: {
                username_top: {
                    required:true,
                    email: true
                },
                password_top: {
                    required: true,
                    minlength: 7
                }        
            },
            messages: {
                username_top: "",
                password_top: {
                    required: "",
                    minlength: ""
                }        
            }
        });
    });
});