tailieunhanh - Chapter 26: Webchat

Webchat là một chương trình CGI hữu ích cho phép một số người trên World Wide Web để nói chuyện với nhau cùng một lúc. Nó khác với một BBS (hệ thống bảng thông báo), trong đó thông điệp được đọc giờ hoặc vài ngày sau khi chúng được đăng. Khả năng trò chuyện trên web có thể là một cách nhanh chóng để tổ chức một hình 26,1 cho thấy một ví dụ về webchat trông giống như "cuộc họp ảo". Mặc dù cả hai webchat và lưu các tin nhắn WebBBS cho những người khác để đọc, có. | CHAPTER 26 WebChat Overview WebChat is a useful CGI program that allows a number of people on the World Wide Web to talk to one another simultaneously. It differs from a BBS bulletin board system in which the messages are typically read hours or days after they are posted. The ability to chat on the Web can be a quick way to hold a virtual meeting. Figure shows an example of what WebChat looks like. Although both WebChat and WebBBS store messages for other people to read there is a major difference in how the user sees and posts messages. The BBS emphasizes long-term storage of messages including statistical data such as the date and time the message is posted. The BBS also encourages users to branch out into different topics in threads of replies. 683 Chapter 26 WebChat On the other hand WebChat emphasizes the quick posting of small messages much like a conversation among a group of people. Dialogue is designed to flow swiftly in small easily digested chunks. Additionally because the topic is being discussed by everyone at the same time there is little room for different people discussing many different things in the same chat session. Thus there is no reason to keep track of different threads of conversation. Figure An example dialogue in WebChat. Because people are discussing things simultaneously in real time another feature of WebChat is the ability to refresh or display new messages as quickly as desired. This is done using the META HTML tag to force refreshes within a certain time frame. WebChat includes many features designed to facilitate this kind of dialogue. In WebChat users can refresh messages using a button that is 684 Chapter 26 WebChat displayed in plain view. In addition if the user is using a browser such as Netscape that supports the META REFRESH HTML tag the user can choose to have the chat messages refresh or redisplay themselves automatically at a user-defined interval. Messages are displayed in chronological order of posting from .