单个页面中有两个xmlHttpRequests-TwoxmlHttpRequestsinasinglepage

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This question

Using two xmlhttprequest calls on a page

在页面上使用两个xmlhttprequest调用

does answer your question.

确实回答了你的问题。

In your request_handler function, you're using a global variable req that gets overwritten every time you call that function.

在request_handler函数中,您使用的是全局变量req,每次调用该函数时都会被覆盖。

If you change it to start:

如果您将其更改为开始:

function request_handler(url, params, changed_div) {
    var req;
    // Rest of your function
}

you should find that it works. In this case req has a local scope and so is not overwritten when you call request_handler for the second time.

你应该发现它有效。在这种情况下,req具有本地范围,因此在第二次调用request_handler时不会被覆盖。

Can I also suggest that you strongly consider using the likes of jQuery, Prototype or Dojo, if you're planning on writing Ajax scripts? Writing scripts that work cross-browsers is hard to do well and these frameworks do a lot of the legwork for you.

如果你打算编写Ajax脚本,我还可以建议你强烈考虑使用jQuery,Prototype或Dojo之类的东西吗?编写跨浏览器的脚本很难做得很好,这些框架为你做了大量的工作。

2  

Your req is a global variable as it is defined without the var keyword, keep that in mind.

您的req是一个全局变量,因为它是在没有var关键字的情况下定义的,请记住这一点。

What I think happens is that the second call overwrites the first one. This is because of the (default) asynchronous nature of the XMLHTTPRequest. Your first function call will end, but the fetching of the page is still going. The second function call then overwrites the previous request.

我认为发生的是第二次调用覆盖了第一次调用。这是因为XMLHTTPRequest的(默认)异步特性。您的第一个函数调用将结束,但页面的获取仍在继续。然后第二个函数调用将覆盖先前的请求。

This however does not explain why both div get filled with the result of the second call. I must say I'm a bit lost on that one.

然而,这并不能解释为什么两个div都填充了第二个调用的结果。我必须说我在那个上有点失落。

0  

This is a pretty common problem, especially if you don't want to take additional measures to block further calls until the first has finished loading. Its a bigger subject that I can cover in a post but there are several examples on the web of an "Ajax Queue" that effectively manages the order of requests received.

这是一个非常常见的问题,特别是如果您不希望采取其他措施来阻止进一步调用,直到第一次完成加载。它是一个更大的主题,我可以在一篇文章中介绍,但网上有几个例子,它们有效地管理收到的请求顺序的“Ajax队列”。

jQuery has a plugin for managing queues and I'm certain that most other Javascript frameworks such as Prototype and MooTools will as well. If you're wanting to stick with raw Javascript I would take a look at this web page:

jQuery有一个用于管理队列的插件,我确信大多数其他Javascript框架,如Prototype和MooTools也是如此。如果您想坚持使用原始Javascript,我会看一下这个网页:

http://www.cmarshall.net/MySoftware/ajax/index.html

He implements a queue very effectively and has an excellent example of its use.

他非常有效地实现了一个队列,并且有一个很好的使用示例。