How do I add a tool to my website that allows you to select your state and city where you live?

I am trying to build a website that is sort of like a dating site. I need my visitors to be able to click on the state that they live in and then the city that they live in. Can anybody tell me where I can find the html for something like that? I also need my visitors to creat their own profile so I need the html on my site so they can do that too. Thank you very much for your help!!