UI scripts are quite similar to script includes. While script includes are blocks of server-side code, accessible to any server-side script, UI Scripts are blocks of code that are available to any client-side script on a page on which they load.

Global UI scripts are relatively simple. They are available on any form in the system, as they are sent from the server to the browser along with all of the other relevant information (the record data, Client Scripts, UI scripts, and other data). When the UI script is set to Global, any other client-side script can access the code within it. For example, imagine that we have a UI Script with the following code in it:

function sayHello() { 
    alert('Hello!'); 
} 

If we mark this UI script as Global, then on any Client Script or UI policy script, we can call sayHello(), and the user will see an alert message that says Hello!.

Furthermore, if we don't wrap the code in a function (or if, in the UI policy, we call the function...