On the auction page, how to synchronously refresh and display the maximum price

On the auction page, how do I synchronously refresh and display the maximum price? There is a product auction page that shows the highest bid of the current product in a div. If a user submits the latest price, all the people who open this page will see the "highest bid" number on the page automatically refresh. This feature has already been implemented by a website, but I have not studied how it works. it seems that it is not the aja auction page. how can I synchronously refresh and display the highest price?
There is a product auction page that shows the highest bid of the current product in a div.

If a user submits the latest price, all the people who open this page will see the "highest bid" number on the page automatically refresh.

This feature has already been implemented by a website, but I have not studied how it works. it seems that it is not ajax refresh every second (if so, it will cause a great burden on the server ).

I suddenly thought of the previous chat room program. when you enter the chat room, even if you don't speak, what others say can be instantly refreshed.

Experts help you give me some advice ......


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Push?
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Use the packet capture tool to catch them and check if they are using the active or passive tools...
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Since yes I didn't know how he did it.How can we say it arbitrarily? Not ajax refresh per second
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Ajax keeps refreshing.
Json data.
Http://www.4.cn/api/auction/live/aid/88261/sid? _ = 1329709450395
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Discussion

Reference:

After waiting for a long time, I didn't see any refresh ....

Http://www.4.cn/auction/detail/aid/88261

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There is one thing called long-polling. I don't know. yes ...?