Q:

JQuery animate breaks the script but without it the script works

I have written this Jquery:
$(document).ready(function() {
    var offset = $("#menu_list").offset().top;

    $(window).scroll(function() {
        if($(window).scrollTop() >= offset) {
            $("#menu_list").removeClass("menu_list_init");
            $("#menu_list").addClass("menu_overlay");

            $("#menu_list").animate({
                opacity: 0.25;
            }, 5000, function() {
                //nothing here
            });
        }
        else if($("#menu_list").hasClass("menu_overlay")) {
            $("#menu_list").removeClass("menu_overlay");
            $("#menu_list").addClass("menu_list_init");
        }
    });
});

Before putting the animate function in there the code was doing what it was supposed too, that is applying some classes when an element reaches the top of the page, it was making the menu which is in the middle stretch to cover the width of the screen.
I thought I might try out using the animate function in there, so I took the stock code from the JQuery website, however, it doesn't work at all once I put it in there...perhaps there is an obvious reason as too why but I can't see it...

A:

"SyntaxError: missing } after property list"
opacity: 0.25;

remove the ; after the 0.25

