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ScrollBalance.js

A javascript plugin that intelligently uses position: fixed to combat unsightly gaps in multi-column layouts, when columns are of different heights. See http://gregplaysguitar.github.io/ScrollBalance.js/ for a demo.

Installation

With npm:

npm install scrollbalance

or via cdn:

<script type="text/javascript" src="https://www.gitcdn.xyz/repo/gregplaysguitar/ScrollBalance.js/master/ScrollBalance.js"></script>

Usage

Start with side-by-side columns, for example:

<div class="column">...</div>
<div class="column">...</div>
<div class="column">...</div>

Columns could be floated, inline-block or positioned absolutely - the only requirement is that they're side-by-side on the page.

With multiple columns, the tallest will be used as the reference height which the others scroll and fix within. If there's only one column, it will scroll and fix within it's parent element.

Initialize the plugin like so:

var scrollbalance = new ScrollBalance(document.querySelector('.column'), {
  // options
});
scrollbalance.bind();

Options

  • minwidth
    disable the plugin if the screen width is less than this (default 0)
  • threshold
    threshold for activating the plugin, eg the column heights must differ by at least this amount to be affected. (default 100)

Methods

  • initialize: function ()
     Recalculate column heights and positioning, for example if content changes
  • resize: function (winWidth, winHeight)
    Handle a browser resize event
  • scroll: function (scrollTop, scrollLeft)
    Handle a browser scroll event
  • bind: function ()
    Bind resize and scroll to the window's corresponding events
  • unbind: function ()
    Remove resize and scroll from the window's corresponding events
  • disable: function ()
    Disable scrollbalance
  • enable: function ()
    Enable scrollbalance
  • teardown: function ()
    Remove all traces of scrollbalance from the content

Scroll / resize event handling

ScrollBalance.bind() binds to the window's resize and scroll events, but you may want to handle these manually to avoid binding to these events multiple times:

var scrollbalance = new ScrollBalance(document.querySelector('.column'));

window.addEventListener('resize', function () {
  var winWidth =  window.innerWidth;
  var winHeight = window.innerHeight;
  scrollbalance.resize(winWidth, winHeight);

  // other resize behaviour
});

window.addEventListener('scroll', function () {
  var scrollTop = window.scrollY;
  var scrollLeft =  window.scrollX;
  scrollbalance.scroll(scrollTop, scrollLeft);

  // other scroll behaviour
});

Column wrapper div

To avoid changing the position of the columns, ScrollBalance.js creates a wrapper div inside each, and appends the column content dynamically. To avoid this, wrap the column content in a div with the class scrollbalance-inner and this will be used instead. The div should have no styling. E.g.

<div class="column"><div class="scrollbalance-inner">...</div></div>
<div class="column"><div class="scrollbalance-inner">...</div></div>

Dynamic content

If your column heights change dynamically, you'll need to call the initialize method - for example:

var scrollbalance = new ScrollBalance(document.querySelector('.column'));

// add some content here
...

scrollbalance.initialize();

Temporarily disabling the plugin

The plugin can be turned on and off with the enable and disable api methods. For example, for smaller screen sizes where the columns don't have room to float side-by-side:

var scrollbalance = new ScrollBalance(document.querySelector('.column'));

window.addEventListener('resize', function() {
    if (window.innerWidth > 900) {
        scrollbalance.enable();
    }
    else {
        scrollbalance.disable();                    
    }
});

Removing the plugin from an element

The teardown method removes all trace of Scrollbalance from an element. For example:

var scrollbalance = new ScrollBalance(document.querySelector('.column'));
scrollbalance.teardown();

Demo

See http://gregplaysguitar.github.io/ScrollBalance.js/ for a demo.

Sites using ScrollBalance.js

License

The plugin is licensed under the MIT License (LICENSE.txt).

Copyright (c) 2011 Greg Brown