是顺序或并行加载的外部JavaScript文件？ [英] are external javascript files loaded sequentially or parallel?

问题描述

如果我的页面中有多个脚本标签，例如：

if i have multiple script tags in my page like:

    <script src="js/jquery-1.7.min.js" type="text/javascript"></script>
    <script src="js/jquery.jplayer.min.js" type="text/javascript"></script>
    <script src="js/globals.js" type="text/javascript"></script>
    <script src="js/sound.js" type="text/javascript"></script>

我可以依赖以前的代码加载后者的代码已经可用的事实？

can i rely on the fact that code from the previous ones is already available when the latter ones are loaded?

推荐答案

通常，脚本是按顺序下载的（参见此页）：

In general, scripts are downloaded sequentially (see this page):

因为JavaScript代码可以改变web
页面的内容和布局，所以浏览器会延迟呈现脚本
标记之后的任何内容，直到该脚本被下载，解析并执行。
但是，更重要的是，对于往返时间，许多浏览器会阻止
下载资源[例如样式表，图像和其他脚本]
脚本之后的文档，直到这些脚本被
下载并执行。

Because JavaScript code can alter the content and layout of a web page, the browser delays rendering any content that follows a script tag until that script has been downloaded, parsed and executed. However, more importantly for round-trip times, many browsers block the downloading of resources [such as stylesheets, images, and other scripts] referenced in the document after scripts until those scripts are downloaded and executed.

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