如何使用Javascript将节点添加到TreeView控件中

I just wanna learn how to add a node to TreeView control (which takes its data from database with a parent-child relationship). Of course when I select a node the new node I wanna add should be added under the selected one and after adding it into the selected node then I wanna add the new node into database too. I can handle the database part but I don't know how to do the client part.I just wanna learn how to add a node to TreeVie