$('textarea#comment').autoResize({

    // On resize:
    onResize : function() {
        $(this).css({opacity:0.8});

    },
    // After resize:
    animateCallback : function() {
        $(this).css({opacity:1});

    },
    // Quite slow animation:
    animateDuration : 300,
    // More extra space:
    extraSpace : 20

});