I would like to add a button to the Experience Editor ribbon that will open a modal or new window with a set of fields from the context item. I had some custom code to do this with the old Sheer UI ribbon but would like to implement this within the new Speak UI ribbon. I have found Sitecore's documentation to create the button: https://doc.sitecore.net/sitecore_experience_platform/content_authoring/the_editing_tools/the_experience_editor/customize_the_experience_editor_ribbon#_Create_a_new

However, I'm having a hard time finding a good example of what to perform within the execute method of my custom javascript.

What javascript would I need to open a window that displays a pre-configured set of fields that exist on the context item?

I would like to add a button to the Experience Editor ribbon that will open a modal or new window with a set of fields from the context item. I had some custom code to do this with the old Sheer UI ribbon but would like to implement this within the new Speak UI ribbon. I have found Sitecore's documentation to create the button: Customize the Experience Editor ribbon

However, I'm having a hard time finding a good example of what to perform within the execute method of my custom javascript.

What javascript would I need to open a window that displays a pre-configured set of fields that exist on the context item?