Scratchpad provides an environment for experimenting with JavaScript code. You can write, run, and examine the results of code that interacts with the web page.

Scratchpad 提供一种 JavaScript 代码的编辑环境。你能写,执行 并且 查看 代码和Web页面交互的结果

Unlike the Web Console, which is designed for interpreting a single line of code at a time, Scratchpad lets you edit larger chunks of JavaScript code, then execute it in various ways depending on how you want to use the output. 

 Web Console 一次执行一行,和 Web Console 不同的是, Scratchpad 是你可以编辑大段的Javascript代码, 然后取决于你希望如何输出的方式,有多种方式执行这些代码。




Opening Scratchpad

开启 Scratchpad

To open the Scratchpad window, press Shift+F4, or go to the Web Developer menu (which is a submenu in the Tools menu on OS X and Linux), then select Scratchpad. This will open up a Scratchpad editor window, which includes a comment that provides some brief information about how to use Scratchpad. From there you can immediately start writing some JavaScript code to try.

按下 Shift+F4, 开启Scratchpad窗口,或是从Web Developer 菜单 (在OS X 和Linux 中是Tools菜单的子菜单) 中 选择Scratchpad,开启的Scratchpad包含一个提供如何使用Scratchpad的帮助信息的注释。从这里你能直接开始书写代码。



The Scratchpad window looks something like this (on OS X the menu bar is at the top of the screen):

Scratchpad 窗口 看起来如下图 (在OS X中菜单条在屏幕顶部)

A screenshot of the Scratchpad

See Using the Source Editor for documentation about the editor itself, including useful keyboard shortcuts.

如果想了解编辑器本身 或者有用的键盘快捷键,请查看 Using the Source Editor

The File menu offers options to save and load JavaScript code snippets, so you can reuse code later if you like.

文件菜单提供 Javascript 代码的保存和加载,以便以后你能反复使用这些代码。

Code completion and inline documentation

代码补完 和 在线文档

Code completion and type information is only available from Firefox 32 onwards.

代码补完和类型信息功能 只在Firefox 32及以后版本中生效。

From Firefox 32 onwards Scratchpad integrates the tern code analysis engine, and uses that to provide autocomplete suggestions and popups containing information on the current symbol. To list autocomplete suggestions, press Control + Space. To show the popup, press Shift + Space in Firefox 32 or Ctrl + Shift + Space in Firefox 33+.

从 Firefox 32 版本开始 Scratchpad 使用  tern code analysis engine 提供自动补完建议并使用弹出窗口显示当前符号的关于信息。使用 Control + Space 便可以呼出自动补完。如果是为了显示弹出信息, 在Firefox 32中使用Shift + Space ,在Firefox 33+中使用Ctrl + Shift + Space .

For example, try typing "d", then pressing Control+Space. You'll see this:

例如, 键入 d, 然后按下 Control + Space。 你可以看到

The icon next to each suggestion indicates the type, and the currently highlighted suggestion gets a popup with more information. Up and Down arrows cycle through the suggestions and Enter or Tab select the highlighted choice.


If you select document, then addEventListener, then press Shift+Space you'll see a popup that shows a summary of the function's syntax and a short description:

如果你选了document,然后addEventListener,再按下 Shift+Space你就可以看到弹出条显示了函数的语法跟简要的描述。

The "[docs]" link takes you to the MDN documentation for the symbol. But note that the link currently opens in the Scratchpad window, giving you no way to get back to the pad. So don't click that link. This issue is being tracked as bug 1026560.

这个"[docs]"链接指向该标志的MDN文档,但是要注意的是这个链接会在Scratchpad窗口打开,让你没办法返回到pad,所以不要点击那个链接。这个问题已经被追踪为bug 1026560


Once you've written your code, select the code you want to run. If you don't select anything, all the code in the window will be run. Then choose the way you want the code to run using the buttons along the top, using the Execute menu, or using the context menu. The code is executed in the scope of the currently selected tab. Any variables you declare outside of a function will be added to the global object for that tab.


There are four execution options available.



When you choose the Run option, the selected code is executed. This is what you'd use to execute a function or other code that manipulates the content of your page without needing to see the result.



The Inspect option executes the code just like the Run option; however, after the code returns, an object inspector is opened to let you examine the returned value.


For example, if you enter the code:


Then choose Inspect, the object inspector is shown that looks something like this:


Inspecting an object in the Scratchpad


The Display option executes the selected code, then inserts the result directly into your Scratchpad editor window as a comment, so you can use it as a REPL.


Reload And Run

The Reload And Run option is only available in the Execute menu. It first reloads the page, then executes the code when the page's "load" event fires. This is useful for running the code in a pristine environment.

Reload And Run选项只在执行菜单可用,它首先重新加载页面,然后当页面加载完毕执行代码。这在比较古老的运行环境中比较有用。

Running Scratchpad in the browser context

You can run Scratchpad in the context of the browser as a whole rather than a specific web page. This is useful if you are working on Firefox itself or developing add-ons. To do this check "Enable chrome and addon debugging" in the Developer Tool Settings. Once you've done this, the Environment menu has a Browser option; once that's selected, your scope is the entire browser rather than just the page content, as you will see from examining some globals:

你可以在整个浏览器的上下文环境运行Sratchpad,而不只是在指定的网页中。这在你使用Firefox工作或开发插件时很有用。要使用这个请在Developer Tool Settings中确认允许chrome跟插件调试。设置完后环境菜单会有个浏览器选项。选中它的时候,你的作用域就是整个浏览器而不只是页面范围了,从下面的测试中可以看出一些全局变量。

[object ChromeWindow]

[object XULElement]

Keyboard shortcuts

  Windows OS X Linux
Open the Scratchpad Shift + F4 Shift + F4 Shift + F4
Run Scratchpad code Ctrl + R Cmd + R Ctrl + R
Run Scratchpad code, display the result in the object inspector Ctrl + I Cmd + I Ctrl + I
Run Scratchpad code, insert the result as a comment Ctrl + L Cmd + L Ctrl + L
Re-evaluate current function Ctrl + E Cmd + E Ctrl + E
Reload the current page, then run Scratchpad code Ctrl + Shift + R Cmd + Shift + R Ctrl + Shift + R
Save the pad Ctrl + S Cmd + S Ctrl + S
Open an existing pad Ctrl + O Cmd + O Ctrl + O
Create a new pad Ctrl + N Cmd + N Ctrl + N
Close Scratchpad Ctrl + W Cmd + W Ctrl + W
Pretty print the code in Scratchpad Ctrl + P Cmd + P Ctrl + P
Show autocomplete suggestions (new in Firefox 32) Ctrl + Space Ctrl + Space Ctrl + Space
Show inline documentation (Firefox 32 only) Shift + Space Shift + Space Shift + Space
Show inline documentation (Firefox 33 onwards) Ctrl + Shift + Space Ctrl + Shift + Space Ctrl + Shift + Space

Source editor shortcuts

This table lists the default shortcuts for the source editor.

In the Editor Preferences section of the developer tools settings, you can choose to use Vim, Emacs, or Sublime Text key bindings instead.

To select these, visit about:config, select the setting devtools.editor.keymap, and assign "vim" or "emacs", or "sublime" to that setting. If you do this, the selected bindings will be used for all the developer tools that use the source editor. You need to reopen the editor for the change to take effect.

From Firefox 33 onwards, the key binding preference is exposed in the Editor Preferences section of the developer tools settings, and you can set it there instead of about:config.

  Windows OS X Linux
Go to line Ctrl + J Cmd + J Ctrl + J
Find in file Ctrl + F Cmd + F Ctrl + F
Find again Ctrl + G Cmd + G Ctrl + G
Select all Ctrl + A Cmd + A Ctrl + A
Cut Ctrl + X Cmd + X Ctrl + X
Copy Ctrl + C Cmd + C Ctrl + C
Paste Ctrl + V Cmd + V Ctrl + V
Undo Ctrl + Z Cmd + Z Ctrl + Z
Redo Ctrl + Shift + Z / Ctrl + Y Cmd + Shift + Z / Cmd + Y Ctrl + Shift + Z / Ctrl + Y
Indent Tab Tab Tab
Unindent Shift + Tab Shift + Tab Shift + Tab
Move line(s) up Alt + Up Alt + Up Alt + Up
Move line(s) down Alt + Down Alt + Down Alt + Down
Comment/uncomment line(s) Ctrl + / Cmd + / Ctrl + /


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