$(function() {
    $('#user_session_login, #user_session_password, #demo_hub_name')
        .each(function() {
            var $this = $(this);
            if ( $this.val() == '' ) {
                $this.addClass('textbox_off');
            }
            if ( $this.val() != '' ) {
                $this.addClass('textbox_focus');
            }
        })
        .focus(function() {
            var $this = $(this);
            $this.removeClass('textbox_off');
            $this.addClass('textbox_focus');
        })
        .blur(function() {
            var $this = $(this);
            if ( $this.val() == '' ) {
                // user did not type anything, or removed the text
                // set element class back to "off"
                $this.removeClass('textbox_focus');
                $this.addClass('textbox_off');
            }
        })
        ;
});