Over the next couple of posts I'm going to look at the different rollover capabilities that are available for overlays in the MapQuest JavaScript API. To get started I'll post a simple module that can be imported into any application. To demonstrate, I have included links to an application that uses the module. The original Capture the Flag application can be seen here, and with the new functionality, here.
The module accomplishes two things. First, it uses the altState fields of the overlay to change the alpha value of the overlay, making it more transparent. Second, it accepts a string as an argument, using that as a title which is displayed in a rollover window. The following image is a screenshot of the Capture the Flag application, shown with the mouse hovering over the overlay on the left.
