javascript下载

Unlike other languages that can be used in a web browser, JavaScript doesn't need to be downloaded and installed. Browsers that support JavaScript have it built into the browser, where it is turned on by default (meaning that typically, you'll need to change your browser settings only if you don't want the browser to run JavaScript). The only exception is that Internet Explorer also supports vbScript the same way, and the two languages are controlled via settings called "active scripting" rather than a setting that reference JavaScript specifically.

与可在网络浏览器中使用的其他语言不同，不需要下载和安装JavaScript。 支持JavaScript的浏览器已将其内置到浏览器中，默认情况下处于打开状态(这意味着通常，仅当您不希望浏览器运行JavaScript时，才需要更改浏览器设置)。 唯一的例外是Internet Explorer也以相同的方式支持vbScript ，并且这两种语言是通过称为“活动脚本”的设置来控制的，而不是通过专门引用JavaScript的设置来控制的。

What you will need to download with JavaScript, then, is not the scripting language itself, but rather those scripts that you want to run in your web page (assuming that you have decided not to learn JavaScript so you can write it all yourself).

因此，您需要使用JavaScript下载的不是脚本语言本身，而是要在网页中运行的脚本(假设您决定不学习JavaScript，因此可以自己编写)。

JavaScript下载是免费的 ( JavaScript Downloads Are Free )

There is no need to pay for scripts written in JavaScript, because just about any script imaginable is available somewhere as a free JavaScript download. What you need to be careful of, though, is to obtain them from a site that is actually offering the scripts as a free download, rather than just copying the scripts from any site. JavaScript code that performs any significant task will be subject to copyright, so you will permission from the author to use his or her script.

无需为用JavaScript编写的脚本付费，因为几乎可以想象得到的任何脚本都可以通过免费JavaScript下载获得。 但是，您需要注意的是从实际上免费提供脚本的网站上获取它们，而不是仅仅从任何站点复制脚本。 执行任何重要任务的JavaScript代码均受版权保护，因此您将获得作者的允许使用其脚本。

The task the JavaScript is doing is not able to be copyrighted, however, so if you are writing a script yourself, you can't get into trouble for looking at an existing script to see how the programmer did it and then writing your own version. But if you are just looking for free JavaScript downloads, then you should go to a site where the author specifically states that his or her script is available as a free download and can be used on your site. There are many sites that offer free JavaScript downloads, including several huge sites that only offer JavaScript downloads, as well as other sites (such as this one) that offer free JavaScript downloads and also have tutorials on how to write the scripts for yourself.

但是，JavaScript所执行的任务无法获得版权，因此，如果您自己编写脚本，则不必担心查看现有脚本以了解程序员的工作方式，然后编写自己的版本。 但是，如果您只是在寻找免费JavaScript下载，那么您应该去一个网站，在该网站上作者特别声明，他或她的脚本可以免费下载，并且可以在您的网站上使用。 有许多网站提供免费JavaScript下载，包括几个仅提供JavaScript下载的大型网站，以及其他提供免费JavaScript下载并且还提供有关如何为自己编写脚本的教程的网站(例如该网站)。

免费下载JavaScript的优点 ( Advantages of Getting Free JavaScript Downloads )

Apart from avoiding copyright issues, there are other advantages to getting your free JavaScript downloads from a site that is actively offering the scripts. The main one is that such sites usually provide step-by-step instructions on how to actually install and use the script. Where you just grab a script from anywhere, not only are you stealing a script but also you won't get instructions on how to install it or support if you can't get it to work.

除了避免版权问题外，从正在积极提供脚本的网站上免费下载JavaScript还有其他好处。 主要的一点是，此类站点通常提供有关如何实际安装和使用脚本的分步说明。 在任何地方都可以抓取脚本的地方，不仅会窃取脚本，而且如果无法使脚本正常运行，您将不会获得有关如何安装或获得支持的说明。

Another thing to watch for when you are getting your free JavaScript downloads from an appropriate site is that many of these sites have been in existence for many years, and the way that JavaScript should be used has changed over time. In many cases, you'll find scripts that were written many years ago to work on the most popular browsers available at that time -- browsers that are now long gone. Ideally, you should have at least some familiarity with what is currently considered the best way of writing JavaScript, so that you can choose the version that will work best with current browsers.

当您从适当的站点获得免费JavaScript下载时，还要注意的另一件事是，这些站点中的许多已经存在了很多年，并且使用JavaScript的方式已经随着时间而改变。 在许多情况下，您会找到许多年前编写的脚本，这些脚本可以在当时可用的最受欢迎的浏览器上运行，而这些浏览器早已不复存在。 理想情况下，您应该至少对当前被认为是编写JavaScript的最佳方式的知识有所了解，以便可以选择最适合当前浏览器的版本。

You can't really blame the sites offering scripts that are not up to date. It does take time to code and test JavaScripts to make sure that they work correctly with the wide range of browsers in common use today. Having a somewhat dated script that still works available as a free download is certainly better than not having the script available at all. The biggest sites specializing in free JavaScript downloads usually offer scripts written by a lot of different people, and they rely on someone actually writing a new version of a script before they can offer it for download. Other sites that have their own staff to write and test scripts may have limited resources for being able to create updated versions of scripts, and so they may be offering older scripts until they can make updates.

您不能真正怪罪那些提供最新脚本的网站。 确实需要花费一些时间来编写代码和测试JavaScript，以确保它们能够与当今广泛使用的各种浏览器正常工作。 具有过时日期的脚本仍然可以免费下载仍然比完全不提供脚本要好。 专门提供免费JavaScript下载的最大型网站通常会提供由许多不同人编写的脚本，并且它们依赖于实际编写脚本的新版本的人才能提供下载。 其他拥有自己的人员来编写和测试脚本的站点可能具有有限的资源来能够创建脚本的更新版本，因此它们可能会提供较旧的脚本，直到可以进行更新为止。

更新免费JavaScript ( Updating Free JavaScripts )

One thing to remember when you obtain free JavaScripts for your site is that there's no reason to continue running the same version of the script forever. When a more modern version of the script is made available as a free download, you can always update your page and replace the old script with the new one. This is particularly easy where the new version of the script is offered as a direct replacement for the script you are currently using, but it shouldn't be all that hard even if you get it from a completely different source.

在为您的站点获得免费JavaScript时要记住的一件事是，没有理由永远继续运行相同版本的脚本。 免费提供更现代版本的脚本后，您可以随时更新页面，并用新脚本替换旧脚本。 在提供新版本的脚本以直接替换当前使用的脚本的情况下，这特别容易，但是即使从完全不同的来源获得脚本，也不应该那么困难。

The number and variety of scripts offered for free download mean that no matter what sort of JavaScript you want to add to your page, you should be able to find several sites offering one or more variations on such scripts. Only when you get to the stage where you require a script that directly interacts with custom code within your web page (such as for form field validation) will you be unable to find a free JavaScript download that does everything for you without your having to code any of it yourself. Even in such situations, you should be able to find free downloads that provide you with pieces of code that will do at least a part of what you need, along with instructions on how to attach such code fragments together to do what you require.

可免费下载的脚本数量众多，种类繁多，这意味着无论您要添加到页面的哪种JavaScript，您都应该能够找到多个站点，这些站点提供了一个或多个此类脚本的变体。 仅当您到达一个需要脚本与网页内的自定义代码直接交互的阶段(例如用于表单字段验证)时，您才能找到免费JavaScript下载，而无需编写代码即可为您完成所有工作任何你自己。 即使在这种情况下，您也应该能够找到免费下载的文件，这些文件可以为您提供至少可以满足您所需功能的一部分代码，以及有关如何将此类代码片段附加在一起以执行所需功能的说明。

Even those who move on to writing their own JavaScript rather than relying on pre-written free downloads can make use of free downloads. Along with complete scripts for performing a variety of simple tasks, there are also code libraries available as free downloads that will provide common functionality that will make writing your own JavaScript much easier.

即使是那些继续编写自己JavaScript而不是依靠预先编写的免费下载内容的人，也可以使用免费下载内容。 除了用于执行各种简单任务的完整脚本之外，还有免费下载的代码库，这些代码库将提供通用功能，这些功能将使编写自己JavaScript更加容易。

For those want to learn to program, one of the biggest advantages of JavaScript is that it is all free. You don't need to pay for anything to get started. The JavaScript language itself is built into all the browsers you need for testing the scripts, and there are plenty of free JavaScript downloads of complete scripts and libraries that you can either use as is or examine to see how things work in order to write your own code.

对于那些想学习编程的人来说，JavaScript的最大优点之一就是它完全免费。 您无需支付任何费用即可开始使用。 JavaScript语言本身已内置在测试脚本所需的所有浏览器中，并且有大量免费的完整脚本和库JavaScript下载，您可以按原样使用或检查它们的工作方式以编写自己的脚本码。

翻译自: https://www.thoughtco.com/free-javascript-download-2037527

javascript下载