Number Sorting

Sounds like the appropriate solution is to:

1. Write a method for each sort (so it can be called on PHP page build AND via JS XHR [code duplication = bad]);
2. Build the form as you have to refresh the page for each sort option;
3. *Enhance* the page using JavaScript that, when available, calls for the sorted data via XHR when requested.

This assumes you care about scale, maybe your data store isn't/won't be that large.