Why use ajax submission must be alert to assign value

This article shows you why the use of ajax submission must be alert to assign values, the content is concise and easy to understand, can definitely brighten your eyes, through the detailed introduction of this article, I hope you can get something.

A strange problem is that when you use ajax to submit, you assign the return value to a variable. No matter how you write it, you can't assign it. At first, you suspected that js was wrong, but ie didn't react to it, and it didn't work to clear the cache or part of the program many times. In the end, you have to alert one line to see what the reason is; the strange thing is that you can assign values after adding alert, and you can't after deleting alert. Baidu found that it is because ajax is executed asynchronously by default, that is, it does not wait for the completion of the request to start executing the next line of js statements, resulting in an assignment of null.

If you encounter a problem such as a callback function after an ajax request, you should add async:false. Note that if you put quotation marks on false, it will not solve the problem.

The copy code is as follows:

$.ajax ({

Async:false

})

The above is why using ajax submission can only be assigned by alert. Have you learned the knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.