jQuery全局事件和性能?

问题描述

我正在寻找一种使用jQuery显示状态指示器的方法，并且我在jQuery Cookbook中找到了一个解决方案，它显示了该解决方案

I was in search of a way to show a status indicator using jQuery and I found a solution in the jQuery Cookbook, it showed this solution

(function($) {
    $(document).ready(function() {
       $('#ajaxStatus')
         .ajaxStart(function() {
            $(this).show();
        })
         .ajaxStop(function() {
            $(this).hide();
        });

        .....
  })(jQuery);

然后它告诫

所以首先我应该使用上面显示的解决方案，并且随着我的网站和js代码越来越大，这是否会成为性能问题?

So first should I use the solution showed above and will it be a performance issue as my site and js code gets larger and larger?

我应该避免jQuery全局事件，只是像段落中所述将其关闭吗?

Should I avoid jQuery global events, just turn it off like the paragraph says?

最后，你们如何在执行ajax请求时显示一个简单的指示器?

Lastly, how do you guys show a simple indicator while an ajax request is being performed?

推荐答案

老实说，我认为这种警告是有效的，但同时已经过时了.在此处查看jQuery源: http://github.com/jquery/jquery/blob/master/src/event.js#L290

Honestly, I think this caution is valid, but at the same time, outdated. Look at the jQuery source here: http://github.com/jquery/jquery/blob/master/src/event.js#L290

它显示了如何现在处理全局事件:

It shows how a global event is now handled:

if ( jQuery.event.global[ type ] ) {
  jQuery.each( jQuery.cache, function() {
    if ( this.events && this.events[type] ) {
      jQuery.event.trigger( event, data, this.handle.elem );
    }
  });
}

使用是:

jQuery("*").add([window, document]).trigger(type, data);

因此，它不会像以前那样在每个元素上触发，它使大量元素发出警告，这是一个非常现实的问题，而是循环遍历已注册或事件的元素，并且仅当任何已注册，因此现在的性能 更好.

So it's not triggering on every element like it used to, which made the large number of elements warning a very real concern, it instead loops over elements that have registered or the event, and only if any have registered, so it's much better on performance now.

对于您的问题:

是的，上面的解决方案很好，在上面概述了全局事件优化之后，我还没有看到足够大的页面来解决这个问题.

Yes, the solution above is just fine, I've yet to see a page large enough for this to be an issue, after the global events optimization I outlined above.

不是，您几乎可以忽略该段落在此更改之后使用的任何jQuery 制成.

Nope, you can pretty much ignore that paragraph is using any jQuery after this change was made.

与您的问题完全相同:)

Exactly as you have in your question :)

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