I have a disabled TextBox that I am editing the value of on the client side with JavaScript. When I try to retrieve the value on the server side it does not reflect the chan
Browsers don't post values back in disabled input controls, as you've discovered. Probably the easiest way to work around this is to hook onto form submission, and re-enable the input as the form is being submitted; the user won't have a chance to edit the value, and it should get posted with the rest of the request.
An alternative might be to inject a hidden element into the form; this could either be maintained by your script, mirroring the displayed value, or added at the end, in a similar fashion to the above.