Wednesday, March 22, 2017

Announcing Beta Release of Selenium IE Driver

One of the most common question I get asked is, "How can I help contribute to Selenium?" Usually my answer involves pull requests and the like, but today, I can offer a much easier way for people to contribute. A significant part of my attention over the last four years has been thinking about and working on the W3C specification for WebDriver. While the specification codifies many of the things that the open source Selenium project has done for years, there are some significant changes to the wire protocol that the language bindings use to communicate with the drivers themselves. The specification already has an implementation in wide use, in geckodriver, Mozilla's driver implementation for Firefox. In order to move forward, however, the IE driver needs to be updated to follow the specification. Here's where you come in.

I've modified the IE driver to use the W3C dialect of the wire protocol. This modification, while significant internally, shouldn't show any differences in behavior from the existing, shipping IE driver. It currently passes all of the tests in the Selenium project for IE. While these tests are pretty extensive, the permutations available in the DOM and in Selenium WebDriver code used to automate it are nearly infinite. To that end, I'm announcing the availability of a beta version of the IE driver. What am I asking you to do? Simply download the new driver executable, and use it in place of the existing driver you're using in your Internet Explorer automation.


  • The beta driver should be a drop-in replacement for the existing 3.3.0 IEDriverServer.exe release. It should require no changes in your code, save maybe pointing to the new executable.
  • Having said that, there are some differences that are expected due to spec compliance. Full-page screenshots, for example, are explicitly disallowed by the specification, so are no longer generated by the driver.
  • The beta driver's version number (visible by executing IEDriverServer.exe --version) will be 3.3.99.x. Bug fix releases will increment the "build" (fourth) field of the version number.
  • This executable will only be available via the download site; it will not be available via package managers (Maven, NuGet, npm, etc.). If the beta appears in any of the (unofficial) packages that may be used for IEDriverServer.exe in a package manager, a request will be sent to the package owner to remove it, so please don't rely on those.
  • There have been some extensive internal rewrites due to the nature of the protocol changes. More on what to look for below.
  • Only the 32-bit version of the driver is being provided for the beta.

Areas of Concern

We want to know if there are any differences between the shipping 3.3.0 version of IEDriverServer.exe and the beta version. You should see the same behavior, including bugs; do not expect the beta driver to magically fix issues you may have experienced with IE in the past. Updating to support the specification wire protocol has required extensive rewrites, but these should all be transparent to the language bindings. The biggest changes have happened in the areas of element interactions, so you should pay special attention to things like or WebElement.sendKeys(). There is one known issue that if you call WebElement.submit(), and the onsubmit event handler throws up a JavaScript alert(), the driver will hang. This issue won't be fixed until after the merge back to master. Also note that the beta has to date only been tested against IE 11, and per the driver's current support policy, only officially supports IE 9, 10, and 11.

Reporting Issues

Issues with the beta can be reported to the Selenium project's issue tracker. However, we have to set some ground rules for the issues that you submit. Here they are:
You'll need to provide the following information with any issue report:
  • Language bindings (Java, .NET, Ruby, Python, JavaScript) and version number you're using
  • The specific version of the beta you're using
  • The WebDriver code that behaves differently
  • An HTML page (or link to one) that the WebDriver code can be run against
Lack of any of this information will cause the issue to be closed immediately, without action or investigation! There are simply too many other potential issues with the existing IE driver, and the timeline for getting this merged into the main code line is simply too short to be able to go back and forth with issue reporters trying to set up a reproducible case. Moreover, here are some further guidelines about submitting issues.
  • Prefixing your issue title with "IE Driver Beta" will get it processed more quickly than if you don't.
  • The beta has only been tested with 3.3.x versions of any language bindings. It should still work with any language bindings of the 3.x vintage, but if you haven't tried your code with at least 3.3.x, you will be asked to do so before further investigation can continue on your issue.
  • You should be able to concretely demonstrate a difference in behavior from IEDriverServer.exe 3.3.0 and the beta you're using. If you cannot, you will be asked to do so before investigation can continue.
  • If you are using a test framework, and your sample code cannot be extracted to simple, straightforward WebDriver-only code, your issue will be closed. Developer bandwidth is just too narrow to wade through tons of framework code to get to the single few lines of WebDriver code that are exhibiting different behavior.
  • If you omit an HTML page that can be tested against, your issue will be closed. Again, this may seem overly restrictive, but without this caveat, it will be nearly impossible to debug the issue with the beta driver.
This is pretty time-sensitive, so if you'd like to give this a try, the Selenium project developers would really appreciate it.


  1. Terrific work Jim!

    If anyone needs a reliable set of HTML page examples to write your tests against, check out my open-source web app

  2. The IE driver is still broken with IE11 (I have not tried other IE versions.) I get the dreaded Script.cpp(494) -2147024891 [Access is denied.]: Unable to execute code, call to IHTMLWindow2::execScript failed error on 4 different Windows systems (Windows Server 2008 R2, Windows Server 2012, Windows 7, Windows 10). Is there any way I can help to debug this?