Store settings (selected index) in a text file

Store settings (selected index) in a text file

I have a web project in Visual Studio and I have had some problems with page postback when it comes to my drop down list, so using JQuery instead and the select change function is a smoother solution.

Now I don't just want to play around with the drop down list, but I need to be able to store the selected index as well. So I have a save button and whatever option the user selects, I need to store in a text file. The point is that the next time the page is loaded I need to load the text file and retrieve the settings (selected index) so the drop down list is loaded with the right index that currently was selected when saving the settings.

Is it possible to store selected index in a text file, as well as open it again to retrieve the right index? So I need to set the right index back in the drop down list. Could this be done purely with JQuery, or do I need PHP as well?