Hey ElaKat,
thanks for the quick response. You were right about the tutorials -- good guidance up front saves time later.
This one helped me the most:
http://captivatedev.com/2011/04/06/captivate-javascript-series-part-4- setting-captivate-variables/
For what it's worth, that line of script does replace all instances of a given substring. W3 schools has a nice tool for quickly trying out code. For my purposes here I found links from this page to be helpful: http://w3schools.com/js/js_obj_string.asp
Thanks again!