Differences between Ajax synchronization and Asynchronization

For example: Normal B/S mode (synchronous) Ajax technology (asynchronous)
Synchronization: submit a request, wait for the server to process, and return the result. The client browser cannot do anything during this period.
Asynchronous: requests are triggered through events-> server processing (the browser can still do other tasks)-> processing is complete
Bytes --------------------------------------------------------------------------------------------------------------------
Synchronization means that you ask me to go to dinner. When I hear it, I will go to dinner with you. If I don't hear it, you will not stop calling until I tell you to hear it.
Asynchronous mode means that you call me and then eat on your own. After receiving the message, I may leave immediately or wait until I get off work.

Therefore, if I want to invite you to dinner, I will use the synchronous method. If I want to invite you to dinner, I will use the asynchronous method, so that you can save money.
Bytes --------------------------------------------------------------------------------------------------------------------
For example, synchronous message sending during a call is asynchronous.

Let's look at several parameters of the open method.

. Open (http-method, URL, async, userid, password)

(The account and password are followed. the user name and password are required on the HTTP page that prohibits anonymous access)

First, let's look at the asynchronous processing method.

Async is a Boolean value. If it is an asynchronous communication method (true), the client will not wait for the server to respond; if it is a synchronous mode (false), the client will wait until the server returns a message before executing other operations. We need to specify the synchronization mode based on actual needs. In some pages, multiple requests may be sent, or even highly-intensive requests with organized and planned structures, the other will overwrite the previous one. In this case, you must specify the synchronization mode: flase.