The program under the server performs a network request. Ask how to solve the card problems

The program on the server performs a network request. How can I solve the card problem? A network request is sent to the server. This request is sent using ajax. But the server gets stuck at this time. You can request other pages only after the request is complete. If the request is not completed at this time. Other pages are stuck there. How can this problem be solved ?, The program on your title server performs a network request. How can I solve the card problem?
A network request is sent to the server. This request is sent using ajax. But the server gets stuck at this time. You can request other pages only after the request is complete. If the request is not completed at this time. Other pages are stuck there. How can this problem be solved?

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Your title confused me. Is a program on the server performing a network request? Is the request initiated by the browser? Or are requests initiated by server programs? Where does ajax come from?
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The server sends a request? Get data from other servers?
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This is not why some servers are stuck.
This is the introduction of jquery ajax on w3school (http://w3school.com.cn/jquery/ajax_ajax.asp)

Async
Type: Boolean
Default value: true. By default, all requests are asynchronous requests. To send a synchronization request, set this option to false.
Note: The synchronous request locks the browser. Other operations can be performed only after the request is completed.
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The answer is synchronous or asynchronous. try again later.