Simple UiKit for complex web apps
JavaScript Ruby
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UKI – simple UiKit for complex Web apps

Uki is a JavaScript user interface toolkit for desktop-like web applications. It comes with a rich view-component library ranging from Sliders to Grids and SplitPanes.

uki({ view: 'Button', text: 'Click me', rect: '10 10 100 24' }).attachTo( window );

uki('Button[text^=Click]').click(function() { alert(this.text()); });

All you have to know in 5 minutes

  1. Uki interfaces are created from Views the same way web pages are created from DOM nodes. Views even behave similar to DOM nodes. You can appendChild, insertBefore, access parent etc.


    Examples of views: Slider, SplitPane or Table (

  2. View have attributes. You can read them by calling attrname() without params and write with attrname(newValue).

    label.text('Lorem') // set text to a label
    label.text() == 'Lorem' // get text
    splitPane.handlePosition(300) // move the split pane handle to 300px
  3. You can create Views with uki() function. Once created view can be attached to any block DOM container with attachTo()

    uki({ view: 'Label', text: 'Lorem', ... more attributes ... }).attachTo( window )
  4. You can find attached views using css-like selectors.

    uki('Label') // find all labels on page
    uki('Box[name=main] > Label') // find all immediate descendant Labels in a box with name = "main"
  5. uki() calls return Collection of Views. This is similar to jQuery('expression') result. You can access individual views with [index]. You can manipulate all views at the same time with a number of collection methods (

    uki('Label')[2] // get 3-d found label
  6. Events are bound to Views (not individual DOM nodes) with the bind() function

    uki('Label')[0].bind('click', function() {  handle the event here  }) // bind click to the first label
    uki('Label').bind('click', function() {  handle the event here  }) // bind click to all labels
    uki('Label').unbind('click') // unbind all click handlers from all labels
  7. Views are laid out with initial position and resize rules. Initial position is set with the rect property

    button.rect('50 20 100 22') // set left = 50px, top = 20px, width = 100px, height = 22px

    Resize rules are set with the anchors property:

    button.anchors('left top') // stay at the left top when container resizes
    button.anchors('right bottom') // move with the bottom right corner of the container
    button.anchors('left top right') // stay at the top, resize width with the container

    You can pass both rect and anchors to the uki() function:

    uki({ view: 'Button', rect: '50 20 100 22', anchors: 'left top right' })
  8. You can change visual appearance of the views with themes. Theme is basically a collection of resources like images, styled dom nodes and backgrounds. You can find an example of one at

  9. If your adding uki to existing project then it is better to simply add

    <script src=''></script>

    to your pages and it will work. If you start a new one you might try uki-tools (

  10. See the available resources in Links section and have fun


* API docs at
* Google group
* Code examples at
* Development docs and tutorial at
* Google wave in 100 lines of code example:


To install development server

  1. Install ruby

  2. Open terminal and run

    gem install uki
    cd PATH_TO_UKI
    uki run

Image path

For older browsers uki loads images from server. By default development version loads them from uki.theme.airport.imagePath. To point it to your development server do

uki.theme.airport.imagePath = ''


The Web should be simple. Adding a new library to your app should not require using a specific build process or learning a new language. It should be as simple as adding a <script> tag to your HTML. That's exactly the way uki works. No frameworks to install, no dependencies to manage, no CSS to include. Simple.


I can imagine living in a fairy-tale world where any browser supports HTML 5 and there's no such thing as IE6 :) Unfortunately, reality is different. I have to support all the browser flavors available, even the dinosaurs. That's why uki works with IE6+, Opera 9+, FF 2+, Safari 3+, and Chrome. And it looks exactly the same on any of them.


One of the reasons uki appeared is that I had to create a 4000-row complex client-side-searchable table. Just rendering the table made any version of IE unresponsive for half a minute. Uki uses progressive rendering and can render 30k+-row lists and tables mostly instantly.


With all the images packed into it (not supported in IE6 and IE7), a gzipped uki build is under 30kb, and it's a single HTTP request.


Creating a new component requires only one function to redeclare.


It's great when you start building your whole app with uki. But sometimes you have to add a desktop-like experience to a working site. Say, adding a widget or a table to an existing design. While uki can occupy the whole browser window, it works perfectly well in a small <div> in your sidebar. Just use attachTo( myDiv ) for any widget you want to add.

You already know it

Uki is written in plain JavaScript. It leverages well-known DOM and JS idioms such as CSS selectors, events and attributes. If you've ever used jQuery, learning uki won't take long.

Programmable Layout

HTML and CSS are great technologies, though you can't lay everything out with them. There are things that require programmable layout calculations. Think of a toolbar, which should show a popup when some of the buttons don't fit. Or a split pane. Or moving a slider bar on window resize. That's the reason uki calculates view positions and sizes with JavaScript. Unfortunately, resizing everything with pure JS will make your layout slow as a turtle. So uki uses as much native browser layout as possible.

Longer example

{   // create a split pane...
    view: 'SplitPane', rect: '1000 600', anchors: 'left top right bottom',
    handlePosition: 300, leftMin: 200, rightMin: 300,
    // ...with button on the left
    leftChildViews: { view: 'Button', rect: '10 10 280 24', anchors: 'top left right', text: 'Clear text field' },
    // ...and a vertical split pane on the right...
    rightChildViews: [
       { view: 'VSplitPane', rect: '693 600', anchors: 'left top right bottom', vertical: true,
           // ...with text field in the top part
           topChildViews: { view: 'TextField', rect: '10 10 280 24', anchors: 'top left', value: '0', id: 'field' },
           // ...and a slider in the bottom
           bottomChildViews: { view: 'Slider', rect: '10 10 673 24', anchors: 'top right left' }
}).attachTo( window, '1000 600' );

// on slider change update text field
uki('SplitPane Slider').bind('change', function() {

// on button click clear the text field
uki('Button[text~="Clear"]').bind('click', function() {
    uki('#field').value('') // find by id

results in


    view: 'Button',
    rect: '400 40 200 24',
    text: 'uki is awesome!'
}).attachTo( document.getElementById('test'), '1000 100' );

uki('Button[text^=uki]').click(function() {
    alert('Hello world!');

  { view: "Button", text: "Click me", rect: "10 10 100 24" }
).attachTo( document.getElementById("test") );

  function() { alert(this.text()); }

uki({ view: 'SplitPane', rect: '1000 600', anchors: 'left top right bottom', 
    handlePosition: 300, autogrowLeft: false, leftMin: 300, rightMin: 300,
    leftChildViews: { view: 'Button', rect: '10 10 280 24', anchors: 'top left right', text: 'left pane' },
    rightChildViews: [
        { view: 'SplitPane', rect: '693 600', anchors: 'left top right bottom', vertical: true,
            topChildViews: { view: 'Button', rect: '10 10 280 24', anchors: 'top left', text: 'top pane' },
            bottomChildViews: { view: 'Slider', rect: '10 10 673 24', anchors: 'top right left' }
}).attachTo( window, '1000 600' );


cd tests
narwhal runner.js


And one more thing. Unobtrusive JavaScript is evil.