How can I make a div stick to the top of the screen once it's been scrolled to?

Question

I would like to create a div, that is situated beneath a block of content but that once the page has been scrolled enough to contact its top boundary, becomes fixed in place

Answer 1

You've seen this example on Google Code's issue page and (only recently) on Stack Overflow's edit page.

CMS's answer doesn't revert the positioning when you scroll back up. Here's the shamelessly stolen code from Stack Overflow:

function moveScroller() {
    var $anchor = $("#scroller-anchor");
    var $scroller = $('#scroller');

    var move = function() {
        var st = $(window).scrollTop();
        var ot = $anchor.offset().top;
        if(st > ot) {
            $scroller.css({
                position: "fixed",
                top: "0px"
            });
        } else {
            $scroller.css({
                position: "relative",
                top: ""
            });
        }
    };
    $(window).scroll(move);
    move();
}

<div id="sidebar" style="width:270px;"> 
  <div id="scroller-anchor"></div> 
  <div id="scroller" style="margin-top:10px; width:270px"> 
    Scroller Scroller Scroller
  </div>
</div>

<script type="text/javascript"> 
  $(function() {
    moveScroller();
  });
</script> 

And a simple live demo.

A nascent, script-free alternative is position: sticky, which is supported in Chrome, Firefox, and Safari. See the article on HTML5Rocks and demo, and Mozilla docs.

Answer 2

Here's one more version to try for those having issues with the others. It pulls together the techniques discussed in this duplicate question, and generates the required helper DIVs dynamically so no extra HTML is required.

CSS:

.sticky { position:fixed; top:0; }

JQuery:

function make_sticky(id) {
    var e = $(id);
    var w = $(window);
    $('<div/>').insertBefore(id);
    $('<div/>').hide().css('height',e.outerHeight()).insertAfter(id);
    var n = e.next();
    var p = e.prev();
    function sticky_relocate() {
      var window_top = w.scrollTop();
      var div_top = p.offset().top;
      if (window_top > div_top) {
        e.addClass('sticky');
        n.show();
      } else {
        e.removeClass('sticky');
        n.hide();
      }
    }
    w.scroll(sticky_relocate);
    sticky_relocate();
}

To make an element sticky, do:

make_sticky('#sticky-elem-id');

When the element becomes sticky, the code manages the position of the remaining content to keep it from jumping into the gap left by the sticky element. It also returns the sticky element to its original non-sticky position when scrolling back above it.

Answer 3

Here's an example that uses jquery-visible plugin: http://jsfiddle.net/711p4em4/.

HTML:

<div class = "wrapper">
    <header>Header</header>
    <main>
        <nav>Stick to top</nav>
        Content
    </main>
    <footer>Footer</footer>
</div>

CSS:

* {
    margin: 0;
    padding: 0;
}

body {
    background-color: #e2e2e2;
}

.wrapper > header,
.wrapper > footer {
    font: 20px/2 Sans-Serif;
    text-align: center;
    background-color: #0040FF;
    color: #fff;
}

.wrapper > main {
    position: relative;
    height: 500px;
    background-color: #5e5e5e;
    font: 20px/500px Sans-Serif;
    color: #fff;
    text-align: center;
    padding-top: 40px;
}

.wrapper > main > nav {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    font: 20px/2 Sans-Serif;
    color: #fff;
    text-align: center;
    background-color: #FFBF00;
}

.wrapper > main > nav.fixed {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
}

JS (include jquery-visible plugin):

(function($){

    /**
     * Copyright 2012, Digital Fusion
     * Licensed under the MIT license.
     * http://teamdf.com/jquery-plugins/license/
     *
     * @author Sam Sehnert
     * @desc A small plugin that checks whether elements are within
     *       the user visible viewport of a web browser.
     *       only accounts for vertical position, not horizontal.
     */
    var $w = $(window);
    $.fn.visible = function(partial,hidden,direction){

        if (this.length < 1)
            return;

        var $t        = this.length > 1 ? this.eq(0) : this,
            t         = $t.get(0),
            vpWidth   = $w.width(),
            vpHeight  = $w.height(),
            direction = (direction) ? direction : 'both',
            clientSize = hidden === true ? t.offsetWidth * t.offsetHeight : true;

        if (typeof t.getBoundingClientRect === 'function'){

            // Use this native browser method, if available.
            var rec = t.getBoundingClientRect(),
                tViz = rec.top    >= 0 && rec.top    <  vpHeight,
                bViz = rec.bottom >  0 && rec.bottom <= vpHeight,
                lViz = rec.left   >= 0 && rec.left   <  vpWidth,
                rViz = rec.right  >  0 && rec.right  <= vpWidth,
                vVisible   = partial ? tViz || bViz : tViz && bViz,
                hVisible   = partial ? lViz || rViz : lViz && rViz;

            if(direction === 'both')
                return clientSize && vVisible && hVisible;
            else if(direction === 'vertical')
                return clientSize && vVisible;
            else if(direction === 'horizontal')
                return clientSize && hVisible;
        } else {

            var viewTop         = $w.scrollTop(),
                viewBottom      = viewTop + vpHeight,
                viewLeft        = $w.scrollLeft(),
                viewRight       = viewLeft + vpWidth,
                offset          = $t.offset(),
                _top            = offset.top,
                _bottom         = _top + $t.height(),
                _left           = offset.left,
                _right          = _left + $t.width(),
                compareTop      = partial === true ? _bottom : _top,
                compareBottom   = partial === true ? _top : _bottom,
                compareLeft     = partial === true ? _right : _left,
                compareRight    = partial === true ? _left : _right;

            if(direction === 'both')
                return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop)) && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
            else if(direction === 'vertical')
                return !!clientSize && ((compareBottom <= viewBottom) && (compareTop >= viewTop));
            else if(direction === 'horizontal')
                return !!clientSize && ((compareRight <= viewRight) && (compareLeft >= viewLeft));
        }
    };

})(jQuery);

$(function() {
    $(window).scroll(function() {
        $(".wrapper > header").visible(true) ?
            $(".wrapper > main > nav").removeClass("fixed") :
            $(".wrapper > main > nav").addClass("fixed");
    });
});