This question is similar, but doesn\'t highlight any possibilities to export the data. Thoughts?
I'm not aware of any Javascript libraries which can make an Excel file. But you could simply export it as HTML or CSV - note that Javascript cannot make files (yet), but the working draft of HTML caters for this: http://www.w3.org/TR/file-writer-api/
Excel is quite good at reading tables made in HTML, so you could simply do that and open the HTML file with Excel.
You can create a file for download using Downloadify: https://github.com/dcneiner/Downloadify