Asynchronous Calls in SharePoint with JQuery

I am pretty new to SharePoint development. I need your suggestions on using jQuery with Sharepoint. I want to do some asynchronous calls to database like cascading DropDowns etc. Like in normal web site we can create a page开发者_如何学C and call cs methods from JQuery. My question is how about SharePoint, how we can achieve the same in SharePoint development.

Please suggest

Kind Regards Vivek

SharePoint will just change the way you deliver the code to your website. Try creating a webpart first. You will need to include a link to jquery in your masterpage.