Firefox Spider

Spider Pro – Easiest Web Scraping Tool – Firefox Add-ons

This extension is paid and requires a license to use it. Spider Pro is the easiest tool to scrape the internet. Simply point and click to turn websites into organized data and download them as JSON/CSV. No coding or configurations required. Unlike other web scraping softwares, it requires only one time payment to scrape for unlimited time and data. No more subscriptions or huge fee for your small projects! Featured on HackerNews, Indiehackers and are you enjoying Spider Pro – Easiest Web Scraping Tool? If you think this add-on violates Mozilla’s add-on policies or has security or privacy issues, please report these issues to Mozilla using this don’t use this form to report bugs or request add-on features; this report will be sent to Mozilla and not to the add-on add-on needs to:Download files and read and modify the browser’s download historyStore unlimited amount of client-side dataAccess your data for all websites
SpiderMonkey - Wikipedia

SpiderMonkey – Wikipedia

SpiderMonkeyDeveloper(s)Mozilla FoundationMozilla
Written inC, C++, RustOperating systemCross-platformPlatformIA-32, x86-64, ARM, MIPS, SPARC[1]TypeJavaScript engineLicenseMPL 2. 0[2]
SpiderMonkey is the first JavaScript engine, written by Brendan Eich at Netscape Communications, later released as open source and currently maintained by the Mozilla Foundation. It is still used in the Firefox web browser. [3]
Eich “wrote JavaScript in ten days” in 1995, [4]
having been “recruited to Netscape with the promise of ‘doing Scheme’ in the browser”. [5]
(The idea of using Scheme was abandoned when “engineering management [decided] that the language must ‘look like Java'”. )[5] In late 1996, Eich, needing to “pay off [the] substantial technical debt” left from the first year, “stayed home for two weeks to rewrite Mocha as the codebase that became known as SpiderMonkey”. [4] (Mocha was the original working name for the language. )[5][6]
In 2011, Eich transferred management of the SpiderMonkey code to Dave Mandelin. [4]
SpiderMonkey version history
Release date
Corresponding ECMAScript version
Browser version
Added functionality
1. 0
March 1996
Netscape Navigator 2. 0
1. 1
August 1996
Netscape Navigator 3. 2
June 1997
Netscape Navigator 4. 0 – 4. 05
1. 3
October 1998
ECMA-262 1st + 2nd edition
Netscape Navigator 4. 06-4. 7x
1. 4
Netscape Server
1. 5
November 2000
ECMA-262 3rd edition
Netscape Navigator 6, Firefox 1. 6
November 2005[7]
Firefox 1. 5
additional array methods, array and string generics, E4X
1. 7
October 2006
Firefox 2. 0
iterators and generators, let statement, array comprehensions, destructuring assignment
1. 8
June 2008
Firefox 3. 0
generator expressions, expression closures
1. 8. 5
March 2011
ECMA-262 5th edition
Firefox 4. 0
JSON support
1. 8
January 2012
Firefox 10. 0
November 2012
Firefox 17. 0
September 2013
Firefox 24. 0
July 2014
Firefox 31. 0
May 2015
Firefox 38. 0
March 2016
Firefox 45. 0
March 2017
Firefox 52. 0
May 2018
Firefox 60. 0
July 2019
Firefox 68. 0
June 2020
Firefox 78. 0
Firefox 90. 0
SpiderMonkey implements the ECMA-262 specification (ECMAScript). ECMA-357 (ECMAScript for XML (E4X)) was dropped in early 2013. [8]
SpiderMonkey is written in C/C++ and contains an interpreter, the IonMonkey JIT compiler, and a garbage collector.
TraceMonkey[9] was the first JIT compiler written for the JavaScript language. Initially introduced as an option in a beta release and introduced in Brendan Eich’s blog on August 23, 2008, [10] the compiler became part of the mainline release as part of SpiderMonkey in Firefox 3. 5, providing “performance improvements ranging between 20 and 40 times faster” than the baseline interpreter in Firefox 3. [11]
Instead of compiling whole functions, TraceMonkey was a tracing JIT, which operates by recording control flow and data types during interpreter execution. This data then informed the construction of trace trees, highly specialized paths of native code.
Improvements to JägerMonkey eventually made TraceMonkey obsolete, especially with the development of the SpiderMonkey type inference engine. TraceMonkey is absent from SpiderMonkey from Firefox 11 onward. [12]
JägerMonkey, internally named MethodJIT, was a whole-method JIT compiler designed to improve performance in cases where TraceMonkey could not generate stable native code. [13][14] It was first released in Firefox 4 and eventually entirely supplanted TraceMonkey. It has itself been replaced by IonMonkey.
JägerMonkey operated very differently from other compilers in its class: while typical compilers worked by constructing and optimizing a control-flow graph representing the function, JägerMonkey instead operated by iterating linearly forward through SpiderMonkey bytecode, the internal function representation. Although this prohibits optimizations that require instruction reordering, JägerMonkey compiling has the advantage of being very fast, which is useful for JavaScript since recompiling due to changing variable types is frequent.
Mozilla implemented a number of critical optimizations in JägerMonkey, most importantly polymorphic inline caches and type inference. [15]
The difference between TraceMonkey and JägerMonkey JIT techniques and the need for both was explained in a article. A more in-depth explanation of the technical details was provided by Chris Leary, one of SpiderMonkey’s developers, in a blog post. More technical information can be found in other developer’s blogs: dvander, dmandelin.
IonMonkey was a JavaScript JIT compiler of Mozilla, which was aimed to enable many new optimizations that were impossible with the prior JägerMonkey architecture. [16]
IonMonkey was a more traditional compiler: it translated SpiderMonkey bytecode into a control-flow graph, using static single assignment form (SSA) for the intermediate representation. This architecture enabled well-known optimizations from other programming languages to be used for JavaScript, including type specialization, function inlining, linear-scan register allocation, dead code elimination, and loop-invariant code motion. [17]
The compiler can emit fast native code translations of JavaScript functions on the ARM, x86, and x86-64 platforms. It has been the default engine since Firefox 18. [18]
OdinMonkey is the name of Mozilla’s new optimization module for, an easily compilable subset of JavaScript. OdinMonkey itself is not a JIT compiler, it uses the current JIT compiler. It’s included with Firefox from release 22.
The WarpMonkey JIT replaces the former IonMonkey engine from version 83. [19] It is able to inline other scripts and specialize code based on the data and arguments being processed.
It translates the bytecode and Inline Cache data into a Mid-level Intermediate Representation (Ion MIR) representation. This graph is transformed and optimized before being lowered to a Low-level Intermediate Representation (Ion LIR). This LIR performs register allocation and then generates native machine code in a process called Code Generation.
The optimizations here assume that a script continues to see data similar what has been seen before. The Baseline JITs are essential to success here because they generate ICs that match observed data. If after a script is compiled with Warp, it encounters data that it is not prepared to handle it performs a bailout. The bailout mechanism reconstructs the native machine stack frame to match the layout used by the Baseline Interpreter and then branches to that interpreter as though we were running it all along. Building this stack frame may use special side-table saved by Warp to reconstruct values that are not otherwise available. [20]
SpiderMonkey is intended to be embedded in other applications that provide host environments for JavaScript. An incomplete list follows:
Mozilla Firefox, Thunderbird, SeaMonkey, and other applications that use the Mozilla application framework
Forks of Firefox including the Pale Moon, Basilisk and Waterfox web browsers.
Data storage applications:
MongoDB moved from V8 to SpiderMonkey in version 3. 2[21]
Riak uses SpiderMonkey as the runtime for JavaScript MapReduce operations[22]
CouchDB database system (written in Erlang). JavaScript is used for defining maps, filters, reduce functions and viewing data, for example in HTML format.
Adobe Acrobat and Adobe Reader, Adobe Flash Professional, and Adobe Dreamweaver. Adobe Acrobat DC uses Spidermonkey 24. 2 with ECMA-357 support forward ported. [23][dead link]
GNOME desktop environment, version 3 and later
Yahoo! Widgets, formerly named Konfabulator
FreeSWITCH, open-source telephony engine, uses SpiderMonkey to allow users to write call management scripts in JavaScript
The text-based web browser ELinks uses SpiderMonkey to support JavaScript[24]
Parts of SpiderMonkey are used in the Wine project’s JScript (re-)implementation[25]
Synchronet, a BBS, e-mail, Web, and application server using the SpiderMonkey engine
JavaScript OSA, a SpiderMonkey inter-process communication language for the Macintosh computer
0 A. D., a real-time strategy game
SpiderMonkey is also used in many other open-source projects; an external list is maintained at Mozilla’s developer site. [26]
Sparx Systems Enterprise Architect, a commercial UML, SysML, BPMN, ArchiMate modelling tool: scripts can be created within the project to call the tool’s own API
SpiderMonkey includes a JavaScript Shell for interactive JavaScript development and for command-line invocation of JavaScript program files. [27]
See also[edit]
Rhino (JavaScript engine)
List of ECMAScript engines
^ “1. 8 – SpiderMonkey | MDN”. 10 January 2013. Archived from the original on 2 May 2013. Retrieved 21 March 2013.
^ Mozilla Licensing Policies,, archived from the original on 2 April 2013, retrieved 26 March 2013
^ “Home”. SpiderMonkey JavaScript/WebAssembly Engine. Retrieved 28 August 2021.
^ a b c
Eich, Brendan (21 June 2011). “New JavaScript Engine Module Owner”. Archived from the original on 14 July 2011. Retrieved 1 July 2011.
Eich, Brendan (3 April 2008). “Popularity”. Archived from the original on 3 July 2011. Retrieved 1 July 2011.
Eich, Brendan (19 August 2011). “Mapping the Monkeysphere”. Archived from the original on 13 January 2013. Retrieved 19 August 2011.
^ “New in JavaScript 1. 6”. Archived from the original on 5 September 2015. Retrieved 28 July 2015.
^ “759422 – Remove use of e4x in account creation”. Retrieved 5 February 2013.
^ “JavaScript:TraceMonkey, MozillaWiki”. Retrieved 22 July 2020.
^ “TraceMonkey: JavaScript Lightspeed, Brendan Eich’s Blog”. Retrieved 22 July 2020.
^ Paul, Ryan (22 August 2008). “Firefox to get massive JavaScript performance boost”. Ars Technica. Archived from the original on 6 May 2012. Retrieved 21 March 2013.
^ Nethercote, Nicholas (1 November 2011). “SpiderMonkey is on a diet | Nicholas Nethercote”. Archived from the original on 28 March 2012. Retrieved 21 March 2013.
^ “JaegerMonkey – Fast JavaScript, Always! » Mystery Bail Theater”. 26 February 2010. Archived from the original on 24 March 2013. Retrieved 21 March 2013.
^ Paul, Ryan (9 March 2010). “Mozilla borrows from WebKit to build fast new JS engine”. Archived from the original on 16 April 2012. Retrieved 21 March 2013.
^ “JaegerMonkey – MozillaWiki”. Archived from the original on 23 August 2013. Retrieved 21 March 2013.
^ “Platform/Features/IonMonkey – MozillaWiki”. 11 February 2013. Archived from the original on 8 March 2013. Retrieved 21 March 2013.
^ “IonMonkey: Mozilla’s new JavaScript JIT compiler”. Archived from the original on 8 December 2012. Retrieved 21 March 2013.
^ “Firefox Notes – Desktop”. 8 January 2013. Archived from the original on 2 September 2014. Retrieved 21 March 2013.
^ “Warp: Improved JS performance in Firefox 83 – Mozilla Hacks – the Web developer blog”. Mozilla Hacks – the Web developer blog. 13 November 2020. Retrieved 28 August 2021.
^ “SpiderMonkey — Firefox Source Docs documentation”. Retrieved 28 August 2021.
^ “JavaScript Changes in MongoDB 3. 2 — MongoDB Manual 3. 4”. Archived from the original on 6 June 2017. Retrieved 23 November 2016.
^ “The Release Riak 0. 8 and JavaScript Map/Reduce”. Archived from the original on 3 November 2011. Retrieved 24 April 2011.
^ “Acrobat DC SDK Documentation”. Retrieved 27 February 2020. Core JavaScript engine has migrated to version 24. 2 of SpiderMonkey (the underlying JavaScript engine from Mozilla).
^ Bolso, Erik Inge (8 March 2005). “2005 Text Mode Browser Roundup”. Linux Journal. Archived from the original on 15 March 2010. Retrieved 5 August 2010.
^ wine-cvs mailing list Archived 7 February 2009 at the Wayback Machine, 16 September 2008: “jscript: Added regular expression compiler based on Mozilla regexp implementation”
^ “SpiderMonkey > FOSS”. MDN Web Docs. Retrieved 2 April 2019.
^ “Introduction to the JavaScript shell”. MDN. Mozilla Developer Network. 29 September 2010. Archived from the original on 29 June 2011. Retrieved 14 December 2010. The JavaScript shell is a command-line program included in the SpiderMonkey source distribution. [… ] You can use it as an interactive shell [… ] You can also pass in, on the command line, a JavaScript program file to run [… ]
External links[edit]
Official website, SpiderMonkey (JavaScript-C) engine
Documentation for SpiderMonkey
Spidermonkey’s page for Open Source Links
Are We Fast Yet? (Official benchmark and comparison)
Hack 42. Spider the Web with Firefox

Hack 42. Spider the Web with Firefox

Hack 42. Spider the Web with Firefox
Save lots and lots of web pages to your local
disk without hassle.
If a web page is precious, a simple bookmark might not be enough. You
might want to keep a copy of the page locally. This hack explains how
to save lots of things at once with Firefox. Usually this kind of
thing is done by a web
spider. A web spider is
any program that poses as a user and navigates through pages,
following links.
For heavy-duty web site
spidering done
separately from Firefox, Free Download Manager () for
Windows and wget(1) for Unix/Linux (usually
preinstalled) are recommended.
4. 11. 1. Save One Complete Page
The days of HTML-only page capture are long gone.
It’s easy to capture
a whole web page now.
4. 1 Saving using Web Page Complete
To save a whole web page, choose FileSave Page As… and
make sure that “Save as type:” is
set to Web Page Complete. If you change this option, that change will
become the future default only if you complete the save action while
you’re there. If you back out without saving, the
change will be lost. When the page is saved, an HTML document and a
folder are created in the target directory. The folder contains all
the ancillary information about the page, and the
page’s content is adjusted so that image, frame, and
stylesheet URLs are relative to that folder. So, the saved page is
not a perfect copy of the original HTML. There are two small oddities
to watch out for:
On Windows, Windows Explorer has special smarts that sometimes treat
the HTML page and folder as one unit when file manipulation is done.
If you move the HTML page between windows, you might see the matching
folder move as well. This is normal Windows the page refers to stylesheets on another web site using a tag, these stylesheets will not be
saved. As a result, Firefox will attempt to download these
stylesheets each time the saved HTML copy is displayed. This will
take forever if no Internet connection is present. The only way to
stop this delay is to choose FileWork Offline when viewing
such files.
4. 2 Saving using Print
One problem with saved web pages is that the copy is just a snapshot
in time. It’s difficult to tell from a plain HTML
document when it was captured. A common technique that solves this
problem and keeps all the HTML content together is to use Acrobat
Distiller, which comes with the commercial (nonfree) version of
Acrobat Reader.
When Distiller is installed, it also installs two printer drivers.
The important one is called Acrobat PDFWriter.
It can convert an HTML page to a single date-stamped PDF file.
Although such PDF files are large and occasionally imperfect, the
process of capturing web pages this way is addictive in its
simplicity, and the files are easy to view later with the free (or
full) Reader. The only drawback is that PDF files can be quite large
compared to HTML.
To save web pages as PDF files, choose FilePrint… from
the Firefox menu, choose Adobe PDFWriter as the device, and select
the Print to File checkbox. Then, go ahead and print;
you’ll be asked where to save the PDF results.
4. 2. Save Lots of Pages
To save lots of Web pages, use an extension. The Download Tools
category at lists a number of
likely candidates. Here are a few of them.
4. 1 Down Them All
The Down Them All extension (), invoked from
the context menu, skims the current page for foreign information and
saves everything it finds to local disk. It effectively acts as a
two-tier spider. It saves all images linked from the current page, as
well as all pages linked to from the current page. It
doesn’t save stylesheets or images embedded in
linked-to pages.
Two of the advantages of Down Them All are that it can be stopped
partway through, and download progress is obvious while it is
4. 2 Magpie
Magpie extension ()
provides a minimal interface that takes a little getting used to. For
spidering purposes, the context menu items that Magpie adds are not
so useful. The special keystroke Ctrl-Shift-S, special URLs, and the
Magpie configuration dialog box are the key spidering features.
To find the Magpie configuration system, choose
ToolsExtensions, select the Magpie extension, and then
click Options. Figure 4-21 shows the resulting
dialog box.
Figure 4-21. Magpie configuration window
Using this dialog box, you can set one of two options for
Ctrl-Shift-S (detailed in the radio group at the top). Everything
else in this window has to do with folder names to be used on local
The first time you press Ctrl-Shift-S, Firefox asks you for the name
of an existing folder in which to put all the
Magpie downloads. After that, it never asks again.
By default, Ctrl-Shift-S saves all tabs to the right of the current
one and then closes those tabs. That is one-tier spidering of one or
more web pages, plus two-tier spidering for any linked images in the
displayed pages.
If the “Linked from the current
page… ” option is selected instead, then Magpie
acts like Down Them All, scraping all images (or other specified
content) linked from the current page.
In both cases, Magpie generates a file with the name
(a datestamp) in the target directory and stuffs all the spidered
content in there.
The other use of Magpie is to download collections of URLs that have
similar names. This is like specifying a keyword bookmark, except
that only numbers can be used as parameters and they must be hand
specified as ranges. For example, suppose these URLs are required:
Using the special bkstr: URL scheme (an unofficial
convenience implemented by Magpie), these four URLs can be condensed
down to a single URL that indicates the ranges required:
Retrieving this URL retrieves the four pages listed directly to disk,
with no display. This process is also a one-tier spidering
technology, so retrieved pages will not be filled with any images to
which they might refer. This technique is most useful for retrieving
a set of images from a photo album or a set of documents (chapters,
minutes, diary entries) from an index page.
4. 3 Slogger
Rather than saving page content on demand, the
Slogger extension () saves
every page you ever display. After the initial install, the extension
does nothing immediately. It’s only when you
highlight it in the Extensions Manager, click the Options box, and
choose a default folder for the logged content that it starts to fill
the disk. The configuration options are numerous, and Perl-like
syntax options make both the names of the logged files and the
content of the log audit trail highly customizable.
Since Slogger saves only what you see, how well it spiders depends on
how deeply you navigate through a web site’s
hierarchy. Note that Mozilla’s history mechanism
works the same way as Slogger, except that it stores downloaded web
pages unreadably in the disk cache (if that’s turned
on), and that disk cache can be flushed or overwritten if it fills
4. 3. Learning from the Master
Bob Clary’s CSpider JavaScript library and
XUL Spider application are the
best free tools available for automating web page navigation from
inside web pages. You can read about them here:
These tools are aimed at web programmers with a systematic mindset.
They are the basis of a suite of web page compatibility and
correctness tests. These tools won’t let you save
anything to disk; instead, they represent a useful starting point for
any spidering code that you might want to create yourself.

Frequently Asked Questions about firefox spider

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