Popup Widget
============

The popup widget allows the user to create a simple widget to display
informative text / HTML.

The following code creates a widget to add a simple text description to
the model:

``` {.sourceCode .javascript}
G.addWidget(Widgets.POPUP);
Popup1.setName("Description");
Popup1.setMessage("Model description");
```

An example of how this might look like with simple text and HTML is
shown below:

![image](images/widgets/popup.png)

![image](images/widgets/popup2.png)

Other than for displaying simple text / HTML, the popup widget can be
used to let the user interact with the simulation associating scripts to
user actions via HTML anchor elements. Anchor elements can point to
Geppetto entity nodes via the 'instancepath' attribute, and custom
handlers can be associated to user actions (browser events such as
'click', 'dblclick', etc.) via the addCustomNodeHandler method. The
entity node will be received as a parameter of the custom handler.

An example is shown below:

``` {.sourceCode .javascript}
G.addWidget(Widgets.POPUP);
Popup2.addCustomNodeHandler(function(node){alert(node.getName());}, 'click', 'myDomainType');
Popup2.setMessage("Some HTML here linking to a specific entity <a href="#" instancepath="mySuperEntity.myAspect.MyEntity">entity</a>");
```

In the example above, when the user clicks on the entity link the custom
handler will be invoked if MyEntity is of type myDomainType. The custom
handler takes the entity node as a parameter, coming from the
instancepath attribute of the anchor element. If the value in the
instancepath attribute does not map to an actual entity in the active
Geppetto experiment, the custom handler 'path' parameter will be
undefined.

The domain type is an optional parameter, if omitted the handler will be
applied to all the anchor elements with an 'instancepath' attribute.