jQuery detect if textarea is empty

I am trying to determine if a textarea is empty if a user deletes what is already pre-populated in the textarea using jQuery.

Anyway to do this?

This is what I have and its not working

$(textarea).live('change', function(){
            if($(this).val().length == 0) {
                $(submitButtonClass).addClass('disabled_button');
                $(submitButtonClass).removeClass('transSubmit');
            } else {
                $('.disabled_button').addClass('transSubmit').css({
                    'cursor':'pointer'
                }).removeClass('disabled_button');
            }
        });