Purpose of this demo is to demonstrate, for the theme developer, how to use the customizer postmessage transport and a preview script to toggle complex theme elements on or off.
In this demo I'll toggle displaying the author and post date.
When the post meta is toggled off, the theme will create an post meta wrapper without the post meta html, and the preview script doesn't have anything to toggle:
I solve this by adding the missing html using jQuery.prependTo(). The html is just for the preview and will not be added to the theme:
You'll find a complete demo at GitHub