何时适合使用同步ajax？ [英] When is it appropriate to use synchronous ajax?

问题描述

我刚刚读了另一个关于jQuery同步ajax调用的问题，我想知道：

I was just reading another question about jQuery's synchronous ajax call, and I got to wondering:

什么情况下同步版本一个ajax调用有益/必要？

What circumstances make a synchronous version of an ajax call beneficial/necessary?

理想情况下我想要一个例子，为什么同步比标准的ajax好。

Ideally I'd like an example, and why synchronous is better than standard ajax.

推荐答案

我能想到的唯一合理的例子（无法以其他方式解决）是在<$ c $中拨打电话c> window.onbeforeunload ，其中需要它是同步的，否则页面将继续运行，请求永远不会完成。

The only reasonable example I can think of (that can't be worked around another way) is making a call in window.onbeforeunload, where you need it to be synchronous, or the page will move on and the request will never complete.

在这种使用标准/异步行为的特定情况下，你几乎可以肯定，请求会因为产生任何影响而过早死亡，或者与服务器联系。

In this specific case using standard/asynchronous behavior, you're all but assured the request will die too early to have any impact, or ever contact the server.

我不是说我赞成这样做，恰恰相反（因为它会对用户的浏览速度产生负面影响）。但是......这里没有多少选择。

I'm not saying I'm in favor of doing this, quite the opposite (as it negatively impacts the user's browsing speed). But...there's not much option here.

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