rationale behind today's lecture?

I have a question regrading what we have done today in class.  So we have a HTML sheet that takes all the data entered by the us and transform it into a xsql file.  then we can see what we have entered by typing 'select * from customers;' from oracle.  How does this data got entered into orcale's database?  is there a command that is embedded inside the html file which sends the data into oracle's database?  what role does that xsql file play? could someone please help me? thanks