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1.0.1 • Public • Published


Splittr is a CSS and JavaScript library that implements a very simple GUI splitter for web applicactions. Features include:

  • Resizable and collapsible panels
  • Lightweight: no external libraries (no jQuery or Prototype!)
  • Compatible with W3C-compliant browsers
  • Customizable look and feel
  • Free to use under the terms of the X11 License

The software is not perfect. Find a bug? Want more features? Report it or fork me on Github!


This library can be installed in one of the following ways (from most to least desirable):

  1. Use Bower: bower install splittr
  2. Add this repo as a subrepo in your project
  3. Manually download splittr.min.js and splittr.css and include them in your project

This module is AMD-compliant. If AMD is not present when the script is loaded, the module will put itself on the window.splittr namespace. Otherwise, it will not add any global references to itself.


First, include the JavaScript and CSS libraries.

<script type="text/javascript" src="splittr.min.js"></script>
<link rel="stylesheet" type="text/css" href="splittr.css">

In your HTML, use the data-splittr attribute. It should be of the following format:

direction interactive initialBreadth1 initialBreadth2 ...

where direction is either "horizontal" or "vertical", interactive is either "dynamic" (movable boundaries) or "static" (non-movable boundaries), and initialBreadthN is the initial width/height of the Nth panel in the splitter.

Important: The object containing the data-splittr attribute must have a defined width and height, and it must be position: relative, position: absolute, or position: fixed. All child elements will become position: absolute.

Finally, call the splittr.init() function on the page load:

document.addEventListener("DOMContentLoaded", splittr.init, false);

Making Panels Collapsible

Panels may be made "collapsible", meaning that either of the bordering splitters has a button that enables the panel to be collapsed to zero width/height. To enable a panel to be collapsilbe, add a data-splittr-collapsible attribute.

Customizing Splitters

You may customize the look and size of the splitters.

Splitter Breadth

In JavaScript, set the window.splittr.barBreadth any time before you run the window.splittr.init() function. It should hold a number in pixels that represents the splitter's width/height. Default is 5.

Splitter Colors

In CSS, override the .splittr-bar selector with your own colors. For example, to make a bright blue splitter with black arrows, you could do:

	background: blue;
	color: black;

You may need to mark the overrides with the !important flag.

JavaScript Interface

Resizing Panels Programatically

Panels can be resized programatically using the splittr.resize(element, newSize, anchorNext) function. Parameters are:

  1. element = the HTMLElement which you wish to resize. Must be a child of an initialized Splittr container.
  2. newSize = a number representing the new pizel size of the panel. Splittr assumes that you have checked the bounds.
  3. anchorNext = true if the right side of the panel should stay the same; false or omit if the left size of the panel should stay the same.


The following events are fired on the container element (the one containing the data-splittr attribute):

  • "splittrMove" when a splitter is moved (essentially forwarding the mousemove event)
  • "splittrDone" when a splitter is dropped in a new location

Both events have the following properties:

  • event.prev = the panel to the left or above the splitter
  • event.next = the panel to the right or below the splitter


The following example makes a panel group with three panels stacked on top of each other with splitters in-between each one. The first two panels have collapse handles.

<style type="text/css">
#panel1{ width: 300px; height: 250px; border: 1px solid black; position: relative; }
#panel2{ background-color: #666; }
#panel3{ background-color: #999; }
#panel4{ background-color: #CCC; }
<div data-splittr="horizontal dynamic 100 50" id="panel1">
	<div data-splittr-collapsible id="panel2">
	<div data-splittr-collapsible id="panel3">
	<div id="panel4">

Future Improvements

Features I hope to implement (or merge a pull request) include:

  • Expanding collapsed panels


npm i splittr

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