There are so many different types of screen available. The 'Screebley' has a HDMI output which supports up to 1920x1080 resolution. The Screebley4K does what it says.
In terms of development you can consider that the 'Screenbly' displays a web page on the display and listens for events:
Here some example events:
{'e':'Gribbley1','d':'goto','u':'/swn/svg-gauges' } // go to the SVG gauges page
{'e':'Gribbley1','d':'UI1','u':'hide' } // hide the first UI element
{'e':'Gribbley1','d':'UI2','u':'show' } // show the second UI element
{'e':'Gribbley1', 'd':'Reload'} // reload the page