滚动到顶部时出现褪色问题

Question

I have a site with a fixed side bar containing the site header and then the site content scrolls on the right. I want to fade in a scroll to top button within the header (Sidebar) using something similar to this method http://gazpo.com/2012/02/scrolltop/ but it doesnt seem to be triggering, could it be to do with the site having a fixed sidebar?

How would I re-write the jquery to look out for the scrolling content and not the entire page scrolling

<script type="text/javascript">
$(document).ready(function(){ 

    $(window).scroll(function(){
        if ($(this).scrollTop() > 100) {
            $('.scrollup').fadeIn();
        } else {
            $('.scrollup').fadeOut();
        }
    }); 

    $('.scrollup').click(function(){
        $("html, body").animate({ scrollTop: 0 }, 600);
        return false;
    });

});

Thanks

Answer 1

It could be one of many things (I'm with StreakyCobra - a jsFiddle would be very useful here)

• Did you check that "scrollup" is the class of your button, and not "scrollUp"?

• What are the CSS properties for .scrollup? Is the display set to none, or the opacity to 0? If so, the fade in and fade out can not affect it, as you will be fading in or out something that is already not visible.