JavaScript是多线程的吗？ [英] Is JavaScript multithreaded?

问题描述

这是我的问题 - 我需要使用jQuery.getScript（）动态下载几个脚本并执行某些 JavaScript 加载所有脚本后的代码，所以我的计划是做这样的事情：

Here's my issue - I need to dynamically download several scripts using jQuery.getScript() and execute certain JavaScript code after all the scripts were loaded, so my plan was to do something like this:

function GetScripts(scripts, callback)
{
  var len = scripts.length
  for (var i in scripts)
  {
    jQuery.getScript(scripts[i], function() 
    {
      len --;
      // executing callback function if this is the last script that loaded
      if (len == 0)
        callback()  
    })
  }
}

如果我们假设这只能可靠地工作每个脚本的script.onload事件触发并按顺序和同步执行，因此当两个或多个事件处理程序检查（len == 0）并执行回调方法时，永远不会出现这种情况。

This will only work reliably if we assume that script.onload events for each script fire and execute sequentially and synchronously, so there would never be a situation when two or more of the event handlers would pass check for (len == 0) and execute callback method.

所以我的问题 - 这个假设是正确的，如果不是，那么实现我想要做的是什么？

So my question - is that assumption correct and if not, what's the way to achieve what I am trying to do?

推荐答案

不，JavaScript不是多线程。它是事件驱动的，你按顺序触发事件的假设（假设它们按顺序加载）就是你将看到的。您当前的实施似乎是正确的我相信jQuery的 .getScript（）会注入一个新的< script> 标记，这也应该强制它们加载正确的订单。

No, JavaScript is not multi-threaded. It is event driven and your assumption of the events firing sequentially (assuming they load sequentially) is what you will see. Your current implementation appears correct. I believe jQuery's .getScript() injects a new <script> tag, which should also force them to load in the correct order.

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