window.onbeforeunload执行查询 [英] window.onbeforeunload performing query

问题描述

我正在尝试在用户离开页面时执行帖子查询。我正在使用的代码是

I'm trying to perform a post query when the user leaves the page. The code I'm working with is

<script type="text/javascript">
window.onbeforeunload = function(){
    var used = $('#identifier').val();
    $.post('conversation.php?leave=true',{ud:used});
}
</script>

我在这里做什么有什么问题吗？我在FF错误控制台中得到的结果只是说没有定义其他非相关函数/变量（因为它们正在卸载）。我需要解决的任何提示或指示？

Is there anything wrong with what I'm doing here? The result I get in the FF error console is just saying that other non-related functions/variables are not defined (since they are unloading). Any tips or pointers for what I need to fix?

推荐答案

简单的答案是你无法进行异步AJAX调用可靠地 beforeunload 事件，它将非常在它完成之前终止，因为浏览器垃圾收集页面。你可以进行同步通话，如下所示：

The simple answer is you can't make an asynchronous AJAX call in the beforeunload event reliably, it'll very likely be terminated before it finished, as the browser garbage collects the page. You can make a synchronous call, like this:

$.ajax({ 
  type: "POST", 
  url: 'conversation.php?leave=true', 
  data:{ud:used}, 
  async: false
});

请不要这样做，因为它会抓住你的用户页面持续时间超过需要并阻止它们离开，从而导致负面体验。请注意，这也是在执行时锁定浏览器，在每种情况下都应该避免 async：false 。

Please don't do this though, as it traps your user in the page for longer than needed and prevents them from leaving, resulting in a negative experience. Note that this also locks up the browser while it executes, async: false should be avoided in every case possible.

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