Need help in date paramters

I am looking for and C# code or java script for the below logic.

When I click on the button (load) I want to display start and end dates parameter which will select data from drop down list. and the validation must be end week is lesser than start week.

and the data should be in this format in the drop down list
week1 January 2015
week 2 January 2015
week 3 January 2015
week 4 January 2015
week 5 January 2015

like this for all months ....

once the user select start and end dates they will click on export to see the data in excel.