BleepingComputer.com: Site management

Hello friends I hope your experiences are going to help me find a solution for my needs. Practically I am a novice when it comes to the issues of web hosting and site development. But I have always wanted to make a website of my own with commercial services in it. Probably the scope to hire professionals who can design or develop the site for me has made me even interested. But as I said I am extremely new in these aspects there are some issues in the back of the mind which require clarifications.
The site which would be designed by the developer means he would be knowing about all the codes and scripts etc and in the future if I decide to terminate using his services how would I manage to get those details from him! In that case I would require to know the details about such site development which is not possible for me. Can such professionals be hired in contracts where I would be able to mention all my required clauses so that when he leaves all the essential details are safe with me to be handed over to another professional.
I hope I could make my question clear and would look forward for your answers.

In this case, you have the developer burn you a copy of the code onto disk, or you can do it yourself. Whenever I write code for somebody, I burn them a copy of the code and present it to them with my final bill.