For installation and configuration details about the script, see the main github readme.
Just view the page source code to see how the following examples work. There's no javascript involved: you just need to add specific attributes to your <select> tags.
Examples
Example 1
This is a simple no-frills example. You can lay the fields out in your markup however you want - but for simplicity, the rest of the examples will just put them side to side.
Example 2
Custom default option texts for both the country and region dropdowns.
Example 3
The country dropdown values are by default the same as the display values: the full country names. By adding the data-value="2-char" attribute to the country field, the values will be a 2-char character code.
Example 4
Pre-filling the fields on page load.