This is the Controller for Bookmark Page

BookmarksController

public class BookmarksController {
    public List<Bookmark__c> Bookmarks {get;set;}
    public BookmarksController() {
        Bookmarks = new List<Bookmark__c>();
        Bookmarks = [ 
            SELECT Name
                  ,URL__c
                  ,Short_URL__c
                  ,Category__c
            FROM Bookmark__c
        ];
    }
    
    @RemoteAction 
    public static void saveBookmark( String name, String category, String url ) {
        Bookmark__c bm = new Bookmark__c();
        bm.Name        = name;
        bm.Category__c = category;
        bm.URL__c      = url;
        INSERT bm;
    }
    
    @RemoteAction
    public static void deleteBookmark( String id ) {
        Bookmark__c bm = [
            SELECT Id
            FROM   Bookmark__c
            WHERE  Id  = :id
        ];
        DELETE bm;
    }
    
    @RemoteAction
    public static void shortenUrl( String url,String id  ) {
        GoogleUrlShortener.shortenURL( url, id );    
    }
    
    @RemoteAction
    public static void updateBookmark( String id, String name, String category, String url ) {
        Bookmark__c bm = new Bookmark__c();
        bm.Id          = id;
        bm.Name        = name;
        bm.Category__c = category;
        bm.URL__c      = url;
        UPDATE bm;
    }
}