You can perform many tasks such as expand, collapse, toggle, check, uncheck, select, unselect, etc on the client-side using the clients-side API. To get the client-side instance (object) of the treeview, get it's jQuery selector using its client-side ID and call the getClientSideInstance() method. The method will return the treeview client-side instance which you can later use to call many client-side API methods. Please, refer to the PHP tab on this example for code details.