These docs, like the code itself, are maintained 100% by volunteers
within the Selenium community.
Many have been using it since its inception,
but many more have only been using it for a short while,
and have given their time to help improve the onboarding experience
for new users.
Many members of the community
are present at the #selenium
Libera chat at Libera.chat.
Feel free to drop in and ask questions
and if you get help which you think could be of use within these documents,
be sure to add your contribution!
We can update these documents,
but it is much easier for everyone when we get contributions
from outside the normal committers.
1 - Copyright and attributions
Copyright, contributions and all attributions for the different projects under the Selenium umbrella.
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2 - Contributing to the Selenium site & documentation
Information on improving documentation and code examples for Selenium
Selenium is a big software project, its site and documentation are key
to understanding how things work and learning effective ways to exploit
This project contains both Selenium’s site and documentation. This is
an ongoing effort (not targeted at any specific release) to provide
updated information on how to use Selenium effectively, how to get
involved and how to contribute to Selenium.
Contributions toward the site and docs follow the process described in
the below section about contributions.
The Selenium project welcomes contributions from everyone. There are a
number of ways you can help:
Report an issue
When reporting a new issues or commenting on existing issues please
make sure discussions are related to concrete technical issues with the
Selenium software, its site and/or documentation.
All of the Selenium components change quite fast over time, so this
might cause the documentation to be out of date. If you find this to
be the case, as mentioned, don’t hesitate to create an issue for that.
It also might be possible that you know how to bring up to date the
documentation, so please send us a pull request with the related
If you are not sure about what you have found is an issue or not,
please ask through the communication channels described at
We want to be able to run all of our code examples in the CI to ensure that people can copy and paste and
execute everything on the site. So we put the code where it belongs in the
Each page in the documentation correlates to a test file in each of the languages, and should follow naming conventions.
For instance examples for this page https://www.selenium.dev/documentation/webdriver/browsers/chrome/ get added in these
Each example should get its own test. Ideally each test has an assertion that verifies the code works as intended.
Once the code is copied to its own test in the proper file, it needs to be referenced in the markdown file.
For example, the tab in Ruby would look like this:
The line numbers at the end represent only the line or lines of code that actually represent the item being displayed.
If a user wants more context, they can click the link to the GitHub page that will show the full context.
Make sure that if you add a test to the page that all the other line numbers in the markdown file are still
correct. Adding a test at the top of a page means updating every single reference in the documentation that has a line
number for that file.
Make sure the tab includes text=true. By default, the tabs get formatted
for code, so to use markdown or other shortcode statements (like gh-codeblock) it needs to be declared as text.
For most examples, the tabpane declares the text=true, but if some of the tabs have code examples, the tabpane
cannot specify it, and it must be specified in the tabs that do not need automatic code formatting.
The Selenium project welcomes new contributors. Individuals making
significant and valuable contributions over time are made Committers
and given commit-access to the project.
This guide will guide you through the contribution process.
Step 1: Fork
Fork the project on GitHub
and check out your copy locally.
% git clone email@example.com:seleniumhq/seleniumhq.github.io.git
% cd seleniumhq.github.io
We use Hugo and the Docsy theme
to build and render the site. You will need the “extended”
Sass/SCSS version of the Hugo binary to work on this site. We recommend
to use Hugo 0.110.0 or higher.
Writing good commit messages is important. A commit message
should describe what changed, why, and reference issues fixed (if
any). Follow these guidelines when writing one:
The first line should be around 50 characters or less and contain a
short description of the change.
Keep the second line blank.
Wrap all other lines at 72 columns.
Include Fixes #N, where N is the issue number the commit
fixes, if any.
A good commit message can look like this:
explain commit normatively in one line
Body of commit message is a few lines of text, explaining things
in more detail, possibly giving some background about the issue
being fixed, etc.
The body of the commit message can be several paragraphs, and
please do proper word-wrap and keep columns shorter than about
72 characters or so. That way `git log` will show things
nicely even when it is indented.
The first line must be meaningful as it’s what people see when they
run git shortlog or git log --oneline.
Step 5: Rebase
Use git rebase (not git merge) to sync your work from time to time.
% git fetch origin
% git rebase origin/trunk
Step 6: Test
Always remember to run the local server,
with this you can be sure that your changes have not broken anything.
Pull requests are usually reviewed within a few days. If there are
comments to address, apply your changes in new commits (preferably
fixups) and push to the same
Step 8: Integration
When code review is complete, a committer will take your PR and
integrate it on the repository’s trunk branch. Because we like to keep a
linear history on the trunk branch, we will normally squash and rebase
your branch history.
Our documentation uses Title Capitalization for linkTitle which should be short
and Sentence capitalization for title which can be longer and more descriptive.
For example, a linkTitle of Special Heading might have a title of
The importance of a special heading in documentation
When editing the documentation’s source,
which is written in plain HTML,
limit your line lengths to around 100 characters.
Some of us take this one step further
and use what is called
which is a technique whereby the HTML source lines,
which are not read by the public,
are split at ‘natural breaks’ in the prose.
In other words, sentences are split
at natural breaks between clauses.
Instead of fussing with the lines of each paragraph
so that they all end near the right margin,
linefeeds can be added anywhere
that there is a break between ideas.
This can make diffs very easy to read
when collaborating through git,
but it is not something we enforce contributors to use.
Selenium now has official translators for each of the supported languages.
If you add a code example to the important_documentation.en.md file,
also add it to important_documentation.ja.md, important_documentation.pt-br.md,
If you make text changes in the English version, just make a Pull Request.
The new process is for issues to be created and tagged as needs translation based on
changes made in a given PR.
All references to code should be language independent,
and the code itself should be placed inside code tabs.
To generate the above tabs, this is what you need to write.
Note that the tabpane includes langEqualsHeader=true.
This auto-formats the code in each tab to match the header name,
and ensures that all tabs on the page with a language are set to the same thing.
This code can be automatically displayed in the documentation using the gh-codeblock shortcode.
The shortcode automatically generates its own html, so we do not want it to auto-format with the language header.
If all tabs are using this shortcode, set text=true in the tabpane and remove langEqualsHeader=true.
If only some tabs are using this shortcode, keep langEqualsHeader=true in the tabpane and add text=true
to the tab. Note that the gh-codeblock line can not be indented at all.
One great thing about using gh-codeblock is that it adds a link to the full example.
This means you don’t have to include any additional context code, just the line(s) that
are needed, and the user can navigate to the repo to see how to use it.
If you want your example to include something other than code (default) or html (from gh-codeblock),
you need to first set text=true,
then change the Hugo syntax for the tabto use % instead of < and > with curly braces:
This is preferred to writing code comments because those will not be translated.
Only include the code that is needed for the documentation, and avoid over-explaining.
Finally, remember not to indent plain text or it will rendered as a codeblock.
4 - Musings about how things came to be
Details mostly of interest to Selenium devs about how and why certain parts of the project were created
This is a work in progress. Feel free to add things you know or remember.
How did the Automation Atoms come about?
On 2012-04-04, jimevans asked on the #selenium IRC channel:
“What I wanted to ask you about was the history of the automation atoms. I seem to remember them springing fully formed, as if from the head of Zeus, and I’m sure that wasn’t the case. Can you refresh my memory as to how the concept happened?”
simonstewart then proceeded to tell us a nice little story:
Sure. Are we sitting comfortably? Then I’ll begin. (Brit joke, there)
Imagine wavy lines as the screen dissolves and we’re transported back to when selenium and webdriver were different projects. Before the projects merged, there was an awful lot of congruent code in webdriver. Congruent, but not shared. The Firefox driver was in JS. The IE driver was mostly C++. The Chrome driver was mostly JS, but different JS from the Firefox driver. And HtmlUnit was unique.
We then added Selenium Core to the mix. Yet more JS that did basically the same thing.
Within Google, I was becoming the TL of the browser automation team. And was corralling a framework of our own into the mix. Which was written in JS, and had once been based on Core before it span off on its own path.
So: multiple codebases, lots of JS doing more or less the same thing. And loads of bugs. Weird mismatches of behaviour in edge-cases.
So I had a bit of a think. (Dangerous, I know) The idea was to extract the “best of breed” code from all three frameworks (Core, WebDriver and the Google tool). Break them down into code that could be shared. “The smallest, indivisible unit of browser automation” .
Or “atoms” for short.
These could be used as the basis the everything. Consistent behaviour between browsers. and apis. The other important point was that the JS code in webdriver and core was grown organically. Which is a polite way of saying “I’d rather never edit it again”. Which is a polite way of saying that it was of dubious quality . In places.
So: high quality was important. And I wanted the code broken up into modules. Because editing a 10k LOC file isn’t a bright idea.
Within Google we had a library called Closure. Which not only allowed modularization, but “denormalization” of modules into a single file via compilation. And I knew it was being open sourced. So we started building the library in the google codebase. (Where we had access to the unreleased library, code review tools and our amazing testing infrastructure). Using Closure Library.
“dom.js” was probably the first file I wrote. (We can check). Greg Dennis and Jason Leyba joined in the fun. And the atoms have been growing ever since.
jimevans replied: “molecular drivers?”
And simonstewart finished with:
A Story of Crazy-Fun
Simon Stewart :
So, let’s go back to the very beginning of the project
When it was me, on my own (the webdriver project, that is, not selenium itself) I knew that I wanted to cover multiple different languages, and so wanted a build tool that could work with all of them That is, that didn't have a built in preference for one that made working with other languages painful ant is java biased. As is maven. nant and msbuild are .net biased rake, otoh, supports nothing very well But, and this is key, any valid rake script is also a valid ruby program It's possible to extend rake to build anything So: rake it was The initial rake file was pretty small and manageable But as the project grew, so did the Rakefile Until there was only person who could deal with it (me), and even then it was pretty shaky So, rather than have a project that couldn't be built, I extracted some helper methods to do some of the heavy lifting Which made the Rakefile comprehensible again But they project kept. getting. bigger And the Rakefile got harder and harder to grok At the time, I was working at Google, who have a wonderful build system Google's system is declarative and works across multiple different languages consistently And, most important, it breaks up the build from a single file into little fragments I asked the OSS chaps at Google if it was okay to open source the build grammar, and they gave it the green light So we layered that build grammar into the selenium codebase With one minor change (we handle dictionary args) But that grammar sits on top of rake still, after all this time And there's a problem And that's that rake is single threaded So our builds are constrained to run serially We could use "multitask" types to improve things, but when I've tried that things got very messy, very fast So, our next hurdle is that crazyfun.rb is slow: we need to go faster Which implies a rewrite of crazyfun I'm most comfortable in java So, I've spiked a new version in java that handles the java and js compilation It's significantly faster But, and this is also important, it's a spike The code was designed to be disposable. Now that things have been proved out, I'd really like to do a clean implementation But I'm torn Do I "finish" the new, very fast crazyfun java enough to replace the ruby version?
A story of driver executeables
jimevans noob_einsteinsfo: alright, story time, then. are we sitting comfortably? then we'll begin. noob_einsteinsfo: back when i first started working on the project (circa 2010), the drivers for all of the browsers were built and maintained by the project. at the time, that meant IE, firefox, and chrome. all of those drivers were packaged as part of the selenium standalone server, and were also packaged in with the various language bindings. this was a conscious decision, so that if one were running locally, there would be no need for the java runtime on the machine just to automate a given browser. there were two factors that led to the development of browser drivers as separate executables. as a quick aside, remember that the webdriver philosophy is to automate the browser using the "best-fit" mechanism for that particular browser. for IE, that means using the COM interfaces; for firefox at the time, that meant using a browser extension; for chrome, it also meant a browser extension. so that meant that the IE driver was developed as a DLL in C++ that was loaded by the language bindings, and communicated with via whatever native-code mechanism was provided by the language (JNI for java, P/Invoke for .NET, ctypes for python, etc.). it also meant that the firefox driver was developed as a browser extension that was packaged inside the various language bindings, and extracted, and used in a profile in firefox. as i said, the IE driver was implemented as a DLL, loaded and communicated with using different mechanisms for different language bindings. the problem is that each of those language-specific mechanisms had different load/unload semantics. ruby, for example, would never call the windows FreeLibrary API after loading the DLL into memory, making multiple instances really challenging. *process* semantics, however, as in, starting, stopping, and managing the lifetime of a process on the OS, whatever the OS, are remarkably similar across all languages. so when the IE driver rewrite was completed in 2010, the development team (me) decided to make it a separate executable, so that the load/unload semantics could be consistent no matter what language bindings one was using. concurrently with this, the chromium team made the decision to follow opera's lead and provide a driver implementation for chrome. an implementation that they would develop, enhance, and maintain going forward, relieving the selenium project of the burden of maintaining a chrome driver.
XgizmoX and that driver is part of the browser?
jimevans XgizmoX: not really, but i believe there may be some smarts built into chrome itself that knows when it's being automated via chromedriver. one of the googlers would be a better person to ask about that. anyway, knowing the different in shared library (.dll/.so/.dynlib) loading semantics, the chromium team (with my encouragement) decided to release their chromedriver implementation as a separate executable. fast-forward a couple of years, and you begin to see the effort to make webdriver a w3c standard. a working group with the w3c created a specification (still in progress, but getting close to finished with the first version), which codified the behavior of webdriver, and how a browser should react to its methods. furthermore, it standardized the protocol used to communicate between language bindings and a driver for a particular browser. i can't emphasize how important and groundbreaking this was. because the w3c and the webdriver working group within it are made up of representatives from the browser vendors themselves, it ensures that the solution will be supported directly by the browser vendors. mozilla created their webdriver implementation (geckodriver) for firefox. the most efficient mechanism for distribution of that browser driver, while maintaining the proper semantics for the language bindings, was to ship as a separate executable. note, this is a gross oversimplification of the geckodriver architecture; the actual executable acts as a relatively thin shim, translating from the wire protocol of the spec to their internal marionette protocol but the point still stands. anyway, the landscape is currently evolving regarding browser-vendor-provided driver implementation. microsoft has one for edge, apple has one for safari (10 and above), the chromium team (largely staffed by googlers) has one for chrome, and now mozilla has one for firefox. given the limited utility of the legacy firefox driver going forward, breaking it out into a separate executable would be wasted effort. this is particularly so, since all of the communication bits that are normally handled by the executable (listening for and responding to http requests from the language bindings) are handled entirely by the browser extension. \ there's literally no need for the legacy firefox driver to be a separate executable. moreover, making it independent of a language runtime would be a significant portion of work (because a .NET shop might reasonably balk at being required to install, say, the java runtime just to automate firefox) so historically speaking, noob-einsteinsfo, that's the general reason for why separate executables have become the norm, and why that paradigm wasn't extended to include the legacy firefox driver. does that make sense? okay. now. about geckodriver. the tale of geckodriver is intimately bound with the status of the aforementioned w3c webdriver spec. level 1 of the specification is mostly done, though it took a number of years of effort to get there. it took a large effort from some very smart people (AutomatedTester among them) to mold the initial documentation of what the webdriver open source software (OSS) project did into proper specification language that could be interpreted and turned into actionable stuff by a browser vendor or other implementor. when beginning the geckodriver (nee marionette) project, mozilla decided to base their implementation on the spec, and only the spec, not following the OSS implementation. this created something of a chicken-and-egg problem, in that while the spec language wasn't completed, it couldn't be implemented. it's only been in the last six months or so that the language concerning the advanced user interactions api (the Actions class in java and .NET) has been made robust enough to actually implement. accordingly, that's the single biggest missing chunk of functionality in geckodriver at present. it wasn't implementable via the spec, so it hasn't been implemented. i do know that it's a very high priority for AutomatedTester and his team to get that implementation done and available. as for why geckodriver is mandatory, and the default implementation for automating firefox in 3.x, that also comes down to some decisions made by mozilla.
TheSchaf so i guess there is no other choice than to use the old FF as long as required features are missing WhereIsMySpoon TheSchaf: if you need those features, yes or use another browser TheSchaf well, moveTo and sendKeys should be pretty basic :p
jimevans TheSchaf: element.sendKeys works just fine. it's Actions.sendKeys that would be broken. in firefox version fortysomething (i misremember the exact version), there was a feature added that blocked browser extensions that hadn't been signed by the mozilla security team. remember that the legacy firefox driver was built as a browser extension? well, with that feature of the browser enabled, the legacy driver couldn't be loaded by the browser. now, for several versions of firefox, it was possible to disable this feature of the browser, and allow unsigned extensions to continue to be loaded. and selenium did this, by virtue of the settings used in the anonymous profile the bindings created when launching firefox. until firefox 48, at which point, it was no longer possible to disable loading of unsigned extensions. at that point, geckodriver was the only way forward for that. now, two more slight points, then i'll be done with story time. first, by nature of what the legacy driver extension does, it's not possible to get it to pass the certification process of the mozilla security team. we asked, were denied, and were told it wouldn't happen ever, full stop. and that's perfectly reasonable, since what that extension does is a security hole big enough to drive a whole fleet of lorries through. second, it turns out there may, in fact, be a way to privately sign the legacy extension so that it can be loaded and used privately by versions of firefox 48 and higher. that's still a less-than-ideal approach, because there's no way that our merry band of open source developers can know how to automate firefox better than the development teams at mozilla, who create the browser in the first place. i totally get the frustration that geckodriver doesn't have the full feature parity of the legacy implementation, especially when it feels like one is being forced to move to it. raging at the selenium project about that decision is directing one's ire in entirely the wrong direction. however, before going off and saying horrible things about mozilla's decisions, do know that mozilla has several people who are constantly engaged in the project, a few of them right here in this very channel (AutomatedTester, davehunt, to name two). i'm sure i've glossed over or mischaracterized some of the historical details of these things, and i'm happy to be corrected. i'm old, after all, and the memory isn't what it used to be. but that, my friends, is the (not so very) short history of why we have separate executables for drivers, and why geckodriver is the way forward, and why a move to it was necessary when the move was made even though some functionality was lacking.
jimevans feels like he's become an unofficial historian of the webdriver project