Populate a Word file?

I can use the Javascript library jsPDF.js to create a PDF from user-entered variables in a Captivate file. Is there a way to do something similar with inserting variables into fields in a Word document? There is a website that offers a service to merge an online web form into a Word file, as the Word file is setup with fields where the information gets inserted, but I wanted to know if anyone knew of a way to do this using another method.