Getting Started

To include the source files for Drag and Drop and its dependencies, first load the YUI seed file if you haven't already loaded it.

<script src="http://yui.yahooapis.com/3.18.1/build/yui/yui-min.js"></script>

Next, create a new YUI instance for your application and populate it with the modules you need by specifying them as arguments to the YUI().use() method. YUI will automatically load any dependencies required by the modules you specify.

<script>
// Create a new YUI instance and populate it with the required modules.
YUI().use('dd', function (Y) {
    // Drag and Drop is available and ready for use. Add implementation
    // code here.
});
</script>

For more information on creating YUI instances and on the use() method, see the documentation for the YUI Global Object.

Using Drag and Drop

Basic Drag

You create a simple Drag instance by including the dd-drag module and using the following code:

YUI().use('dd-drag', function(Y) {
    var dd = new Y.DD.Drag({
        node: '#drag'
    });
});

Basic Proxy Drag

You create a simple Proxy Drag instance by including the dd-drag and dd-proxy modules and using the following code:

YUI().use('dd-drag', 'dd-proxy', function(Y) {
    var dd = new Y.DD.Drag({
        node: '#drag'
    }).plug(Y.Plugin.DDProxy); //This config option makes the node a Proxy Drag
});

Basic Drop Target

You create a simple Drop Target instance by including the dd-drop module and using the following code:

YUI().use('dd-drop', function(Y) {
    var drop = new Y.DD.Drop({
        node: '#drop'
    });
});

Using a Drag Handle

Drag handles allow you to specify what element will initiate a drag. For example, you may want the entire element to be able to be dragged, but you only want them to click on the header to do that (in case you have content that will not react well to a drag, like an input or an anchor).

<div id="demo">
    <h2>Drag Me Here</h2>
    <p>Can't drag me here</p>
</div>

Using the addHandle method on the Drag instance, you can tell the Drag to only be started if the user clicks on that element. Any selector string will work here.

var dd = new Y.DD.Drag({
    node: '#demo'
}).addHandle('h2');

You can also use the removeHandle method to remove a previously added handle.

Invalid Handles

The opposite of handles are Invalid Handles. This is a selector string that will never fire a drag event. By default the following HTML elements will not be draggable since adding the mouse events to them prohibit their actual use: textarea, input, a, button, select, [contenteditable]

If you need to drag one of these items, you will have to call removeInvalid on your Drag instance to remove it from the default list.

<ul>
    <li><a href="#"><img src="foo.png"></a></li>
</ul>

Now you create your Drag instance as usual, but call removeInvalid to allow the img to be dragged from inside the li.

var dd = new Y.DD.Drag({
    node: 'ul li'
}).removeInvalid('a');

Events

Drag and Drop for YUI 3 has been been packed with useful events to allow the implementer to control the end user experience.

* All Drag and Drop events bubble, by default, to the Drag and Drop Manager.

Event Bubbling

To allow for a truly Event driven application, all Drag and Drop related events are bubbled to the DragDropMgr.

This allows you to listen for all Drag and Drop events from a central location, per YUI instance.

This approach is also handy for situations where you are dynamically adding and removing items.

So instead of doing this:

var doSomething = function() {
    Y.log('Do Something Here');
};
dd1.on('drag:drag', doSomething);
dd2.on('drag:drag', doSomething);
dd3.on('drag:drag', doSomething);
dd4.on('drag:drag', doSomething);
dd5.on('drag:drag', doSomething);
dd6.on('drag:drag', doSomething);
dd7.on('drag:drag', doSomething);
dd8.on('drag:drag', doSomething);
dd9.on('drag:drag', doSomething);

You can now do this:

var doSomething = function() {
    Y.log('Do Something Here');
};
Y.DD.DDM.on('drag:drag', doSomething);

Delegate Dragging

Delegate dragging allows you to create a "list/group" of draggable items that are under a common "container". Using this approach, you can have hundreds of draggable items, yet only have one object created under the hood.

This approach is also handy for situations where you are dynamically adding and removing items from the "list" and need to make them draggable. Using Delegate you wouldn't have to create a new drag instance when adding or removing it.

YUI().use('dd-delegate', function(Y) {
    var del = new Y.DD.Delegate({
        container: '#demo', //The common container
        nodes: '.item' //The items to make draggable
    });
});

Note: DD.Delegate does not auto find your drop target items, if you change the nodes under the hood (add or remove) you need to call delegate.syncTargets(); to manage them.

CSS Class Names

The Drag and Drop Utility adds CSS class names for important moments in the drag and drop operation. Below you will find the list of these class names.

The Drag and Drop Utility doesn't ship with a default skin, so no style rules are attached to these class names. That is completely left up to the implementer.

Note: As of version 3.1.0, Drag and Drop changed it's classname prefix from yui-dd to yui3-dd to mimic the global change in skinning.

Touch/Gesture Support

Native gesture support was added to DD in 3.2.0. This support is transparent and the implementor should not have to do anything to use this functionality. When dd is used, loader will check the device to see if it contains support for Gesture Events, if the device supports these events the dd-gestures module will automatically be loaded as well as it's dependencies. At this point, DD will operate as usual but it will utilize the native gesture events instead of mouse based events.

Module Descriptions

Drag and Drop for YUI 3 has been broken up into several modules to allow you, as the implementer, to pick how you want it to work and what code you need on your page.

DD Plugins

In 3.2.0, some modules have been removed from the rollup and were converted to DD Plugins. Below are the list of plugins that are no longer in the dd rollup.