php-How to exit the dead loop? What are the advantages of reverse Ajax?

Reverse ajaxphp dead Loop

In PHP, for example, I use a dead loop when using reverse Ajax, and after I close my browser, I manually insert data into the database, but I find that the inserted data is automatically updated (consistent with the effect of entering the dead loop).
Then I looked at the memory occupancy rate and began to realize that the dead loop could not be exited by closing the browser.
So I don't get it,
1, reverse Ajax Why to use the dead loop, memory will not explode? Where is the advantage?
2. How can the dead loop exit?

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