For beginners, questions about php folder generation

Cainiao asked for help. regarding The php folder generation issue, I would like to talk about my requirements online first: there are four radio buttons in the from form, which are, the following text box is used to create the name of the folder to be generated (for example, a). when you click the 2011 button, enter the 2011 folder and create a folder named a under the folder, likewise, you can choose Cainiao for help. you may have questions about php folder generation, online, etc.
First, let's talk about my requirements: There are four single-choice buttons in the from form, which are and respectively. the following text box is used to create the name of the folder to be generated (such as ), when you click the 2011 button, the 2011 folder is displayed, and a folder named a is created under the folder. if you select 2012, the folder is displayed in the 2012 folder ......, My folders such as and so on are all under the upload folder under the xuexi project. please kindly advise. thank you first ......
------ Solution --------------------
Assume that you use the get method to submit
$ Folder = $ _ GET ['Folder']; // The value of a single folder
$ Dir = $ _ GET ['dir'];
Mkdir ('upload/'. $ folder.'/'. $ dir );

The code for creating ajax can be searched on the Internet.