和其他许多人一样，我的网站也在使用jQuery.当我打开开发人员工具时，我看到一条警告，说明XMLHttpRequest是
deprecated because of its detrimental effects to the end user's experience.
I went on and read part of the documentation, but it was fairly technical. Can someone explain the consequences of shifting from XMLHTTPRequest to WHATWG in simple terms? It says it happened in 2012.
此外，文档还指出，workers外部的同步XMLHttpRequest正在从web平台上删除，当这种情况发生时，如果用户代理将它们包含在服务中，它们是否需要修改现有代码？
To avoid this warning, do not use:
async: false
in any of your $.ajax() calls. This is the only feature of XMLHttpRequest that's deprecated.
默认值为async: true，因此如果您从未使用过此选项，那么如果真的删除了该功能，代码应该是安全的.
However, it probably won't be -- it may be removed from the standards, but I'll bet browsers will continue to support it for many years. So if you really need synchronous AJAX for some reason, you can use async: false and just ignore the warnings. But there are good reasons why synchronous AJAX is considered poor style, so you should probably try to find a way to avoid it. And the people who wrote Flash applications probably never thought it would go away, either, but it's in the process of being phased out now.
Notice that the Fetch API that's replacing XMLHttpRequest does not even offer a synchronous option.