javascript - Window.unload 触发后卸载

Question

我正在尝试在卸载页面之前向服务器发帖，然后我关注了 this它工作正常。我的问题是 window.unload 上的 $.post 在它卸载后 被触发。我尝试使用注销链接并检查我的日志，我得到以下信息:

Started GET "/signout" for 127.0.0.1 at 2012-11-22 00:15:08 +0800
Processing by SessionsController#destroy as HTML
Redirected to http://localhost:3000/
Completed 302 Found in 1ms


Started GET "/" for 127.0.0.1 at 2012-11-22 00:15:08 +0800
Processing by HomeController#index as HTML
  Rendered home/index.html.erb within layouts/application (0.4ms)
  Rendered layouts/_messages.html.erb (0.1ms)
Completed 200 OK in 13ms (Views: 12.9ms)


Started POST "/unloading" for 127.0.0.1 at 2012-11-22 00:15:08 +0800
Processing by HomeController#unloading as */*
  Parameters: {"p1"=>"1"}
WARNING: Can't verify CSRF token authenticity
Completed 500 Internal Server Error in 0ms

NoMethodError (undefined method `id' for nil:NilClass):
  app/controllers/home_controller.rb:43:in `unloading'

第一部分是注销，然后用户被重定向到 root 然后它运行帖子('/unloading')。

有没有办法让 '/unloading' 先执行，然后执行卸载操作？

我把这个作为我的 jquery 帖子

$(window).unload ->
  $.ajax {
    async: false,
    beforeSend: (xhr) ->
      xhr.setRequestHeader('X-CSRF-Token', $('meta[name="csrf-token"]').attr('content'))
    , url: '/unloading'
    , type: 'Post'
    , data: {
      p1: '1'
    }
  }

更新

所以我确实将 ajax 请求传输到 beforeunload 并且它正在工作，但我必须执行 return null 以删除出现的对话框，因为如果我不这样做，ajax 仍在触发弹出对话框(即使没有回答“是/否我想离开此页面”)。结果是这样的:

window.onbeforeunload ->
  $.ajax {
    async: false,
    beforeSend: (xhr) ->
      xhr.setRequestHeader('X-CSRF-Token', $('meta[name="csrf-token"]').attr('content'))
    , url: '/unloading'
    , type: 'Post'
    , data: {
      p1: '1'
    }
  }
  return null

此外，我目前只在 Chrome 上尝试过，它按预期工作。尚未尝试其他浏览器。

Answer 1

尝试 beforeUnload 事件

The exact handling of the unload event has varied from version to version of browsers. For example, some versions of Firefox trigger the event when a link is followed, but not when the window is closed. In practical usage, behavior should be tested on all supported browsers, and contrasted with the proprietary beforeunload event.

• https://developer.mozilla.org/en-US/docs/DOM/window.onbeforeunload

更新

卸载页面时触发卸载事件。

• https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest/Synchronous_and_Asynchronous_Requests#XMLHttpRequests_being_stopped

更新 2

要禁用 Are you sure that you want to leave this page? 弹出窗口尝试从 beforeUnload 回调函数返回 null

• How to show the "Are you sure you want to navigate away from this page?" when changes committed?

更新 3

检查跨浏览器兼容性

• http://jonathonhill.net/2011-03-04/catching-the-javascript-beforeunload-event-the-cross-browser-way/