# IE Driver Server

> The Internet Explorer Driver is a standalone server that implements the WebDriver specification.

URL: https://deploy-preview-2974--selenium-dev.netlify.app/documentation/legacy/ie_driver_server/
Site index: https://deploy-preview-2974--selenium-dev.netlify.app/llms.txt

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This documentation previously located [on the wiki](https://github.com/SeleniumHQ/selenium/wiki/InternetExplorerDriver-Internals)

The `InternetExplorerDriver` is a standalone server which implements WebDriver's wire protocol.
This driver has been tested with IE 11, and on Windows 10. It might work with older versions
of IE and Windows, but this is not supported.

The driver supports running 32-bit and 64-bit versions of the browser. The choice of how to 
determine which "bit-ness" to use in launching the browser depends on which version of the 
IEDriverServer.exe is launched. If the 32-bit version of `IEDriverServer.exe` is launched, 
the 32-bit version of IE will be launched. Similarly, if the 64-bit version of 
IEDriverServer.exe is launched, the 64-bit version of IE will be launched.

## Installing

You do not need to run an installer before using the `InternetExplorerDriver`, though some 
configuration is required. The standalone server executable must be downloaded from 
the [Downloads](https://www.selenium.dev/downloads/) page and placed in your 
[PATH](http://en.wikipedia.org/wiki/PATH_(variable)).

## Pros

* Runs in a real browser and supports JavaScript

## Cons

* Obviously the InternetExplorerDriver will only work on Windows!
* Comparatively slow (though still pretty snappy :)

## Command-Line Switches

As a standalone executable, the behavior of the IE driver can be modified through various 
command-line arguments. To set the value of these command-line arguments, you should 
consult the documentation for the language binding you are using. The command line 
switches supported are described in the table below. All -`<switch>`, --`<switch>` 
and /`<switch>` are supported.

| Switch | Meaning |
|:-------|:--------|
| --port=`<portNumber>` | Specifies the port on which the HTTP server of the IE driver will listen for commands from language bindings. Defaults to 5555. |
| --host=`<hostAdapterIPAddress>` | Specifies the IP address of the host adapter on which the HTTP server of the IE driver will listen for commands from language bindings. Defaults to 127.0.0.1. |
| --log-level=`<logLevel>` | Specifies the level at which logging messages are output. Valid values are FATAL, ERROR, WARN, INFO, DEBUG, and TRACE. Defaults to FATAL. |
| --log-file=`<logFile>` | Specifies the full path and file name of the log file. Defaults to stdout. |
| --extract-path=`<path>` | Specifies the full path to the directory used to extract supporting files used by the server. Defaults to the TEMP directory if not specified. |
| --silent | Suppresses diagnostic output when the server is started. |

## Important System Properties

The following system properties (read using `System.getProperty()` and set using
`System.setProperty()` in Java code or the "`-DpropertyName=value`" command line flag) 
are used by the `InternetExplorerDriver`:

| **Property** | **What it means** |
|:-------------|:------------------|
| `webdriver.ie.driver` | The location of the IE driver binary. |
| `webdriver.ie.driver.host` | Specifies the IP address of the host adapter on which the IE driver will listen. |
| `webdriver.ie.driver.loglevel` | Specifies the level at which logging messages are output. Valid values are FATAL, ERROR, WARN, INFO, DEBUG, and TRACE. Defaults to FATAL. |
| `webdriver.ie.driver.logfile` | Specifies the full path and file name of the log file. |
| `webdriver.ie.driver.silent` | Suppresses diagnostic output when the IE driver is started. |
| `webdriver.ie.driver.extractpath` | Specifies the full path to the directory used to extract supporting files used by the server. Defaults to the TEMP directory if not specified. |

## Required Configuration

* The `IEDriverServer` executable must be [downloaded](https://www.selenium.dev/downloads/) and placed in your [PATH](http://en.wikipedia.org/wiki/PATH_(variable)).
* On IE 7 or higher on Windows Vista, Windows 7, or Windows 10, you must set the Protected Mode settings for each zone to be the same value. The value can be on or off, as long as it is the same for every zone. To set the Protected Mode settings, choose "Internet Options..." from the Tools menu, and click on the Security tab. For each zone, there will be a check box at the bottom of the tab labeled "Enable Protected Mode".
* Additionally, "Enhanced Protected Mode" must be disabled for IE 10 and higher. This option is found in the Advanced tab of the Internet Options dialog.
* The browser zoom level must be set to 100% so that the native mouse events can be set to the correct coordinates.
* For Windows 10, you also need to set "Change the size of text, apps, and other items" to 100% in display settings.
* For IE 11 _only_, you will need to set a registry entry on the target computer so that the driver can maintain a connection to the instance of Internet Explorer it creates. For 32-bit Windows installations, the key you must examine in the registry editor is `HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BFCACHE`. For 64-bit Windows installations, the key is `HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BFCACHE`. Please note that the `FEATURE_BFCACHE` subkey may or may not be present, and should be created if it is not present. **Important:** Inside this key, create a DWORD value named `iexplore.exe` with the value of 0.

## Native Events and Internet Explorer

As the `InternetExplorerDriver` is Windows-only, it attempts to use so-called "native", or OS-level 
events to perform mouse and keyboard operations in the browser. This is in contrast to using 
simulated JavaScript events for the same operations. The advantage of using native events is that 
it does not rely on the JavaScript sandbox, and it ensures proper JavaScript event propagation 
within the browser. However, there are currently some issues with mouse events when the IE 
browser window does not have focus, and when attempting to hover over elements.

### Browser Focus

The challenge is that IE itself appears to not fully respect the Windows messages we send the 
IE browser window (`WM\_MOUSEDOWN` and `WM\_MOUSEUP`) if the window doesn't have the focus. 
Specifically, the element being clicked on will receive a focus window around it, but the click 
will not be processed by the element. Arguably, we shouldn't be sending messages at all; rather, 
we should be using the `SendInput()` API, but that API explicitly requires the window to have the 
focus. We have two conflicting goals with the WebDriver project.

First, we strive to emulate the user as closely as possible. This means using native events 
rather than simulating the events using JavaScript.

Second, we want to not require focus of the browser window being automated. This means that 
just forcing the browser window to the foreground is suboptimal.

An additional consideration is the possibility of multiple IE instances running under multiple 
WebDriver instances, which means any such "bring the window to the foreground" solution will 
have to be wrapped in some sort of synchronizing construct (mutex?) within the IE driver's 
C++ code. Even so, this code will still be subject to race conditions, if, for example, the 
user brings another window to the foreground between the driver bringing IE to the foreground 
and executing the native event.

The discussion around the requirements of the driver and how to prioritize these two 
conflicting goals is ongoing. The current prevailing wisdom is to prioritize the former over 
the latter, and document that your machine will be unavailable for other tasks when using 
the IE driver. However, that decision is far from finalized, and the code to implement it is 
likely to be rather complicated.

### Hovering Over Elements

When you attempt to hover over elements, and your physical mouse cursor is within the boundaries 
of the IE browser window, the hover will not work. More specifically, the hover will appear 
to work for a fraction of a second, and then the element will revert back to its previous 
state. The prevailing theory why this occurs is that IE is doing hit-testing of some sort 
during its event loop, which causes it to respond to the physical mouse position when the 
physical cursor is within the window bounds. The WebDriver development team has been unable 
to discover a workaround for this behavior of IE.

### Clicking `<option>` Elements or Submitting Forms and `alert()`

There are two places where the IE driver does not interact with elements using native events. 
This is in clicking `<option>` elements within a `<select>` element. Under normal circumstances, 
the IE driver calculates where to click based on the position and size of the element, typically 
as returned by the JavaScript `getBoundingClientRect()` method. However, for `<option>` elements, 
`getBoundingClientRect()` returns a rectangle with zero position and zero size. The IE driver 
handles this one scenario by using the `click()` Automation Atom, which essentially sets 
the `.selected` property of the element and simulates the `onChange` event in JavaScript. 
However, this means that if the `onChange` event of the `<select>` element contains JavaScript 
code that calls `alert()`, `confirm()` or `prompt()`, calling WebElement's `click()` method will 
hang until the modal dialog is manually dismissed. There is no known workaround for this behavior 
using only WebDriver code.

Similarly, there are some scenarios when submitting an HTML form via WebElement's `submit()` 
method may have the same effect. This can happen if the driver calls the JavaScript `submit()` 
function on the form, and there is an onSubmit event handler that calls the JavaScript `alert()`, 
`confirm()`, or `prompt()` functions.

This restriction is filed as issue 3508 (on Google Code).

## Multiple instances of `InternetExplorerDriver`

With the creation of the `IEDriverServer.exe`, it should be possible to create and use multiple 
simultaneous instances of the `InternetExplorerDriver`. However, this functionality is largely 
untested, and there may be issues with cookies, window focus, and the like. If you attempt to 
use multiple instances of the IE driver, and run into such issues, consider using the 
`RemoteWebDriver` and virtual machines.

There are 2 solutions for problem with cookies (and another session items) shared between 
multiple instances of InternetExplorer.

The first is to start your InternetExplorer in private mode. After that InternetExplorer will be 
started with clean session data and will not save changed session data at quitting. To do so you 
need to pass 2 specific capabilities to driver: `ie.forceCreateProcessApi` with `true` value 
and `ie.browserCommandLineSwitches` with `-private` value. Be note that it will work only 
for InternetExplorer 8 and newer, and Windows Registry 
`HKLM_CURRENT_USER\\Software\\Microsoft\\Internet Explorer\\Main` path should contain key 
`TabProcGrowth` with `0` value.

The second is to clean session during InternetExplorer starting. For this you need to pass 
specific `ie.ensureCleanSession` capability with `true` value to driver. This clears the cache 
for all running instances of InternetExplorer, including those started manually.

## Running `IEDriverServer.exe` Remotely

The HTTP server started by the `IEDriverServer.exe` sets an access control list to only accept 
connections from the local machine, and disallows incoming connections from remote machines. 
At present, this cannot be changed without modifying the source code to the `IEDriverServer.exe`. 
To run the Internet Explorer driver on a remote machine, use the Java standalone remote server 
in connection with your language binding's equivalent of `RemoteWebDriver`.

## Running `IEDriverServer.exe` Under a Windows Service

Attempting to use IEDriverServer.exe as part of a Windows Service application is expressly 
unsupported. Service processes, and processes spawned by them, have much different requirements 
than those executing in a regular user context. `IEDriverServer.exe` is explicitly untested in 
that environment, and includes Windows API calls that are documented to be prohibited to be used 
in service processes. While it may be possible to get the IE driver to work while running under 
a service process, users encountering problems in that environment will need to seek out their 
own solutions.

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Section pages:

- [Internet Explorer Driver Internals](https://deploy-preview-2974--selenium-dev.netlify.app/documentation/legacy/ie_driver_server/internals/index.md): More detailed information on the IE Driver.