How do I set browser width and height in Selenium WebDriver?

I'm using Selenium WebDriver for Python. I want instantiate the browser with a specific width and height. So far the closest I can get is:

driver = webdriver.Firefox()
driver.set_window_size(1080,800)

Which works, but sets the browser size after it is created, and I want it set at instantiation. I'm guessing there is an approach along the lines of:

profile = webdriver.FirefoxProfile();
profile.set_preference(foo, 1080)
driver = webdriver.Firefox(profile)

But I don't know what foo would be, and I can't figure out where the docs are.

Q1: is there a way to set width / height at instantiation?

Q2: Where are the reference docs listing all keys usable by profile.set_preference?

Here is how I do it in Python with Selenium 2.48.0:

from selenium.webdriver import Firefox
driver = Firefox()
driver.set_window_position(0, 0)
driver.set_window_size(1024, 768)

For me, the only thing that worked in Java 7 on OS X 10.9 was this:

// driver = new RemoteWebDriver(new URL(grid), capability);
driver.manage().window().setPosition(new Point(0,0));
driver.manage().window().setSize(new Dimension(1024,768));

Where 1024 is the width, and 768 is the height.

Here's a solution that works with both headless and non-headless mode and will start the window with the specified size instead of setting it after:

Chrome:

from selenium.webdriver import Chrome, ChromeOptions

opts = ChromeOptions()
opts.add_argument("--window-size=2560,1440")

driver = Chrome(options=opts)

Firefox:

from selenium.webdriver import Firefox, FirefoxOptions

opts = FirefoxOptions()
opts.add_argument("--width=2560")
opts.add_argument("--height=1440")

driver = Firefox(options=opts)

Try something like this:

IWebDriver _driver = new FirefoxDriver();
_driver.Manage().Window.Position = new Point(0, 0);
_driver.Manage().Window.Size = new Size(1024, 768);

Not sure if it'll resize after being launched though, so maybe it's not what you want

If you are using chrome

 chrome_options = Options()
 chrome_options.add_argument("--start-maximized");
 chrome_options.add_argument("--window-position=1367,0");
 if mobile_emulation :
     chrome_options.add_experimental_option("mobileEmulation", mobile_emulation)
        
  self.driver = webdriver.Chrome('/path/to/chromedriver', 
                                  chrome_options = chrome_options)

This will result in the browser starting up on the second monitor without any annoying flicker or movements across the screen.

It's easy. Here is the full code.

from selenium import webdriver
driver = webdriver.Chrome()
driver.get("Your URL")
driver.set_window_size(480, 320)

> Make sure chrome driver is in your system path.

Here is firefox profile default prefs from python selenium 2.31.0 firefox_profile.py

and type "about:config" in firefox address bar to see all prefs

reference to the entries in about:config: http://kb.mozillazine.org/About:config_entries

DEFAULT_PREFERENCES = {
    "app.update.auto": "false",
    "app.update.enabled": "false",
    "browser.download.manager.showWhenStarting": "false",
    "browser.EULA.override": "true",
    "browser.EULA.3.accepted": "true",
    "browser.link.open_external": "2",
    "browser.link.open_newwindow": "2",
    "browser.offline": "false",
    "browser.safebrowsing.enabled": "false",
    "browser.search.update": "false",
    "extensions.blocklist.enabled": "false",
    "browser.sessionstore.resume_from_crash": "false",
    "browser.shell.checkDefaultBrowser": "false",
    "browser.tabs.warnOnClose": "false",
    "browser.tabs.warnOnOpen": "false",
    "browser.startup.page": "0",
    "browser.safebrowsing.malware.enabled": "false",
    "startup.homepage_welcome_url": "\"about:blank\"",
    "devtools.errorconsole.enabled": "true",
    "dom.disable_open_during_load": "false",
    "extensions.autoDisableScopes" : 10,
    "extensions.logging.enabled": "true",
    "extensions.update.enabled": "false",
    "extensions.update.notifyUser": "false",
    "network.manage-offline-status": "false",
    "network.http.max-connections-per-server": "10",
    "network.http.phishy-userpass-length": "255",
    "offline-apps.allow_by_default": "true",
    "prompts.tab_modal.enabled": "false",
    "security.fileuri.origin_policy": "3",
    "security.fileuri.strict_origin_policy": "false",
    "security.warn_entering_secure": "false",
    "security.warn_entering_secure.show_once": "false",
    "security.warn_entering_weak": "false",
    "security.warn_entering_weak.show_once": "false",
    "security.warn_leaving_secure": "false",
    "security.warn_leaving_secure.show_once": "false",
    "security.warn_submit_insecure": "false",
    "security.warn_viewing_mixed": "false",
    "security.warn_viewing_mixed.show_once": "false",
    "signon.rememberSignons": "false",
    "toolkit.networkmanager.disable": "true",
    "toolkit.telemetry.enabled": "false",
    "toolkit.telemetry.prompted": "2",
    "toolkit.telemetry.rejected": "true",
    "javascript.options.showInConsole": "true",
    "browser.dom.window.dump.enabled": "true",
    "webdriver_accept_untrusted_certs": "true",
    "webdriver_enable_native_events": "true",
    "webdriver_assume_untrusted_issuer": "true",
    "dom.max_script_run_time": "30",
    }

profile = webdriver.FirefoxProfile()
profile.set_preference('browser.window.width',0)
profile.set_preference('browser.window.height',0)
profile.update_preferences()

write this code into setup part of your test code, before the: webdriver.Firefox() line.

I tried the below code to set the resolution on mac chrome and windows chrome.

driver.manage().window().setSize(new Dimension(1280, 768));

Use the below code to test the resolution changes:-

Dimension dimension = driver.manage().window().getSize();
LOGGER.info("dimension is " + dimension);