How to implement multiple ajax requests

This time I will show you how to implement multiple ajax requests. What are the precautions for implementing multiple ajax requests? The following is a practical case, let's take a look.

When we use ajax to request data, we may encounter the possibility of multiple triggers with one click.

(For example: ajax's onreadystatechange event will be triggered multiple times; this is because onreadystatechange is an event handle.

Its value (state_Change) is a The name of the function, this function will be triggered when the state of the XMLHttpRequest object changes.

The state changes from 0 (uninitialized) to 4 (complete) only when the state is 4. We just execute the code. "

This function will be triggered every time the state of the XMLHttpRequest object changes.

It will be triggered 4 times in total, from 0 to 4.) [PS: Of course here The examples cited in are not completely consistent with the problems encountered at work] At this time, we need a method that can terminate the program.

exit and abort are both used to terminate the program. function, let’s talk about the difference between the two.

##exit will do some release work: Release all . Static global objects, cache, turn off all I/O channels, and then terminate the program. If a function is registered through atexit, the registered function will be called. However, if the atexit function throws an exception, Terminate will be called directly.

##abort: The terminate program immediately, without any cleanup work I believe you have mastered the method after reading the case in this article. , for more exciting information, please pay attention to other related articles on the php Chinese website!

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