--- a/browser/devtools/scratchpad/scratchpad.js
+++ b/browser/devtools/scratchpad/scratchpad.js
@@ -15,27 +15,30 @@
 "use strict";
 
 let require = Components.utils.import("resource://gre/modules/devtools/Loader.jsm", {}).devtools.require;
 
 let { Cc, Ci, Cu } = require("chrome");
 let promise = require("sdk/core/promise");
 let Telemetry = require("devtools/shared/telemetry");
 let TargetFactory = require("devtools/framework/target").TargetFactory;
+const escodegen = require("escodegen/escodegen");
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 Cu.import("resource:///modules/source-editor.jsm");
 Cu.import("resource:///modules/devtools/LayoutHelpers.jsm");
 Cu.import("resource:///modules/devtools/scratchpad-manager.jsm");
 Cu.import("resource://gre/modules/jsdebugger.jsm");
 Cu.import("resource:///modules/devtools/gDevTools.jsm");
 Cu.import("resource://gre/modules/osfile.jsm");
 Cu.import("resource:///modules/devtools/ViewHelpers.jsm");
+Cu.import("resource://gre/modules/reflect.jsm");
+Cu.import("resource://gre/modules/devtools/DevToolsUtils.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "VariablesView",
   "resource:///modules/devtools/VariablesView.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "VariablesViewController",
   "resource:///modules/devtools/VariablesViewController.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "ObjectClient",
@@ -517,16 +520,30 @@ var Scratchpad = {
         });
       }
     }, reject);
 
     return deferred.promise;
   },
 
   /**
+   * Pretty print the source text inside the scratchpad.
+   */
+  prettyPrint: function SP_prettyPrint() {
+    const uglyText = this.getText();
+    try {
+      const ast = Reflect.parse(uglyText);
+      const prettyText = escodegen.generate(ast);
+      this.setText(prettyText);
+    } catch (e) {
+      this.writeAsErrorComment(DevToolsUtils.safeErrorString(e));
+    }
+  },
+
+  /**
    * Writes out a primitive value as a comment. This handles values which are
    * to be printed directly (number, string) as well as grips to values
    * (null, undefined, longString).
    *
    * @param any aValue
    *        The value to print.
    * @return Promise
    *         The promise that resolves after the value has been printed.

--- a/browser/devtools/scratchpad/scratchpad.xul
+++ b/browser/devtools/scratchpad/scratchpad.xul
@@ -41,16 +41,17 @@
   <!-- TODO: bug 650340 - implement printFile()
   <command id="sp-cmd-printFile" oncommand="Scratchpad.printFile();" disabled="true"/>
  -->
 
   <command id="sp-cmd-close" oncommand="Scratchpad.close();"/>
   <command id="sp-cmd-run" oncommand="Scratchpad.run();"/>
   <command id="sp-cmd-inspect" oncommand="Scratchpad.inspect();"/>
   <command id="sp-cmd-display" oncommand="Scratchpad.display();"/>
+  <command id="sp-cmd-pprint" oncommand="Scratchpad.prettyPrint();"/>
   <command id="sp-cmd-contentContext" oncommand="Scratchpad.setContentContext();"/>
   <command id="sp-cmd-browserContext" oncommand="Scratchpad.setBrowserContext();" disabled="true"/>
   <command id="sp-cmd-reloadAndRun" oncommand="Scratchpad.reloadAndRun();"/>
   <command id="sp-cmd-errorConsole" oncommand="Scratchpad.openErrorConsole();" disabled="true"/>
   <command id="sp-cmd-webConsole" oncommand="Scratchpad.openWebConsole();"/>
   <command id="sp-cmd-documentationLink" oncommand="Scratchpad.openDocumentationPage();"/>
   <command id="sp-cmd-hideSidebar" oncommand="Scratchpad.sidebar.hide();"/>
 </commandset>
@@ -89,16 +90,20 @@
   <key id="sp-key-inspect"
        key="&inspect.key;"
        command="sp-cmd-inspect"
        modifiers="accel"/>
   <key id="sp-key-display"
        key="&display.key;"
        command="sp-cmd-display"
        modifiers="accel"/>
+  <key id="sp-key-pprint"
+       key="&pprint.key;"
+       command="sp-cmd-pprint"
+       modifiers="accel"/>
   <key id="sp-key-reloadAndRun"
        key="&reloadAndRun.key;"
        command="sp-cmd-reloadAndRun"
        modifiers="accel,shift"/>
   <key id="sp-key-errorConsole"
        key="&errorConsoleCmd.commandkey;"
        command="sp-cmd-errorConsole"
        modifiers="accel,shift"/>
@@ -267,16 +272,21 @@
   <toolbarbutton id="sp-toolbar-inspect"
                  class="devtools-toolbarbutton"
                  label="&inspect.label;"
                  command="sp-cmd-inspect"/>
   <toolbarbutton id="sp-toolbar-display"
                  class="devtools-toolbarbutton"
                  label="&display.label;"
                  command="sp-cmd-display"/>
+  <toolbarspacer/>
+  <toolbarbutton id="sp-toolbar-pprint"
+                 class="devtools-toolbarbutton"
+                 label="&pprint.label;"
+                 command="sp-cmd-pprint"/>
 </toolbar>
 
 
 <popupset id="scratchpad-popups">
   <menupopup id="scratchpad-text-popup"
              onpopupshowing="goUpdateSourceEditorMenuItems()">
     <menuitem id="se-cMenu-cut"/>
     <menuitem id="se-cMenu-copy"/>

--- a/browser/devtools/scratchpad/test/Makefile.in
+++ b/browser/devtools/scratchpad/test/Makefile.in
@@ -34,14 +34,15 @@ MOCHITEST_BROWSER_FILES = \
 		browser_scratchpad_bug756681_display_non_error_exceptions.js \
 		browser_scratchpad_bug_751744_revert_to_saved.js \
 		browser_scratchpad_bug740948_reload_and_run.js \
 		browser_scratchpad_bug_661762_wrong_window_focus.js \
 		browser_scratchpad_bug_644413_modeline.js \
 		browser_scratchpad_bug807924_cannot_convert_to_string.js \
 		browser_scratchpad_long_string.js \
 		browser_scratchpad_open_error_console.js \
+		browser_scratchpad_pprint.js \
 		head.js \
 
 # Disable test due to bug 807234 becoming basically permanent
 #		browser_scratchpad_bug_653427_confirm_close.js \
 
 include $(topsrcdir)/config/rules.mk

new file mode 100644
--- /dev/null
+++ b/browser/devtools/scratchpad/test/browser_scratchpad_pprint.js
@@ -0,0 +1,26 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test()
+{
+  waitForExplicitFinish();
+
+  gBrowser.selectedTab = gBrowser.addTab();
+  gBrowser.selectedBrowser.addEventListener("load", function onLoad() {
+    gBrowser.selectedBrowser.removeEventListener("load", onLoad, true);
+    openScratchpad(runTests);
+  }, true);
+
+  content.location = "data:text/html;charset=utf8,test Scratchpad pretty print.";
+}
+
+function runTests(sw)
+{
+  const sp = sw.Scratchpad;
+  sp.setText("function main() { console.log(5); }");
+  sp.prettyPrint();
+  const prettyText = sp.getText();
+  ok(prettyText.contains("\n"));
+  finish();
+}

--- a/browser/locales/en-US/chrome/browser/devtools/scratchpad.dtd
+++ b/browser/locales/en-US/chrome/browser/devtools/scratchpad.dtd
@@ -60,16 +60,19 @@
 <!ENTITY inspect.label                "Inspect">
 <!ENTITY inspect.accesskey            "I">
 <!ENTITY inspect.key                  "i">
 
 <!ENTITY display.label                "Display">
 <!ENTITY display.accesskey            "D">
 <!ENTITY display.key                  "l">
 
+<!ENTITY pprint.label                 "Pretty Print">
+<!ENTITY pprint.key                   "p">
+
 <!-- LOCALIZATION NOTE (environmentMenu.label, accesskey): This menu item was
   -  renamed from "Context" to avoid confusion with the right-click context
   -  menu in the text area. It refers to the JavaScript Environment (or context)
   -  the user is evaluating against. I.e., Content (current tab) or Chrome
   -  (browser).
   -->
 <!ENTITY environmentMenu.label        "Environment">
 <!ENTITY environmentMenu.accesskey    "N">