When opening a page where this script enforces the format of a comment, the Save button will be deactivated per default.

Users who do not know how to work with comments, may click the Help button ().

Entering a valid comment will activate the Save button.

If the comment does not meet the constraints, then the page cannot be saved.

If the comment is indicating a new feature, then the checkbox for Notify watchers will be checked.

Typically there is no need to enforce specific comments for each and every change for a page on a Confluence server. Typically versioned documents are located in a specific space. To activate the script for spaces with versioned documents, the 

Configure the space category via the Space Tools.

Once the categories contain a category 'versioned', as specified in the