In previous articles, we covered basics of JQuery. In this series, we will cover one of the plug-in of JQuery called as JQuery UI. JQuery UI extends the JQuery library to provide rich user interface with widgets, effects and interactions. We can download JQuery UI needed components from http://jqueryui.com/download. There will two versions available, one is the latest and other is stable one having fixes for the known bugs. We will work on stable version which is currently 1.7.2. Along with the components, we can specify the theme to be used for those. I will be using "Sunny" theme and downloaded all components as shown below:

1.gif

After downloading, extract the files to a folder "jquery-ui-1.7.2". JQuery UI 1.7.2 is built on top of JQuery library 1.3.2. So, we will be using this version of JQuery library for the demos. Now, we will have a look at folder's structure:

css folder will have the selected theme's CSS and images. js folder will have JQuery library and its UI .js files. development-bundle folder contains demo and documentation for the components and scripts for effects. Index.html will have sample of all UI components.

The components of JQuery UI are: We will cover all these components in depth in coming articles. JQuery UI supports variety of browsers like IE6, 7, 8, Firefox, Opera etc. This library is licensed under MIT and GPL open-source licenses. So, we are free to include it in our code and build applications.

Let's start the demo with interactions. This library provide below interactions: Draggable API allows us to drag an element by mouse within the page or specified container. Below script gives basic dragging feature:

<html>
<head>
 <title>jQuery UI Draggable - Basic</title>
 <!-- This StyleSheet is taken from selected theme "sunny" folder under ..\development-bundle\themes\sunny -->
 <link type="text/css" href="jquery-ui-1.7.2.custom.css" rel="stylesheet" />
 <script type="text/javascript" src="jquery-1.3.2.min.js"></script>
 <!-- These script files are taken from folder ..\development-bundle\ui -->
 <script type="text/javascript" src="ui.core.js"></script>
 <script type="text/javascript" src="ui.draggable.js"></script>
 <script type="text/javascript"> $(function() { $("#draggable").draggable(); });
</script>
</head>
<body>
 <div id="draggable" class="ui-widget-content">
 JQuery Enabled Dragging....</div>
</body>
</html>

We need below files to implement dragging:
  1. jquery-1.3.2.js
  2. ui.core.js
  3. ui.draggable.js
  4. jquery-ui-1.7.2.custom.css taken from 'sunny' theme.
Let's cover other methods and events of Draggable API. We can specify other options on dragging an element as shown below:

<script type="text/javascript">
$(function()
{
$("#draggable").draggable({ containment: '#dragLimit', axis: 'y',delay:500, cursorAt: { cursor: 'move', top: -55, left: -55, bottom: 0 },
stop: function()
{
alert('left:' + $(this).css('left')+', top:'+$(this).css('top'));
}
});
});
</script>
For below div tag:

<div id="dragLimit" style="width:400px;height:400px">
 <div id="draggable" class="ui-widget-content" style="width:100px;height:100px">
 JQuery Enabled Dragging....
 </div>
</div>

containment option specifies the boundary, within which element can be dragged.

axis option will specify in which direction element can be dragged either horizontal or vertical.

delay specifies time in ms to delay the dragging effect.

stop, start and drag specifies functions to be executed.

cursorAt option specifies the properties for cursor style and position, while dragging.

For complete list of methods, events for Draggable API, refer: http://jqueryui.com/demos/draggable/.

I am ending the things here. I am attaching the source code with it. In coming articles, we will cover other interactions provided by JQuery UI in depth. I hope this article will be helpful for all.