平滑滚动到顶部功能

Posted 2021-02-24

Hides the button based on scroll position, fades in and out as necessary and upon click smoothly scrolls back to the top.

$(document).ready(function() {
 
    // hide #back-top first
    $("#back-top").hide();
 
    // fade in #back-top
    $(function() {
        $(window).scroll(function() {
            if ($(this).scrollTop() > 100) {
                $('#back-top').fadeIn();
            } else {
                $('#back-top').fadeOut();
            }
        });
 
        // scroll body to 0px on click
        $('#back-top a').click(function() {
            $('body,html').animate({
                scrollTop: 0
            }, 800);
            return false;
        });
    });
 
});​
 
 
HTML USAGE:
 
<p id="back-top" style="display: block; ">
   <a href="#top"><span></span><em>Back to top</em></a>
</p>