How to set browser viewport size

Question

I'm trying to create a cross-browser Python-Selenium test script. So I need all results to be same no matter which webdriver (Chrome or IE) I use. I can set browser window size as follow:

driver.set_window_size(1920, 1080)

But following code will return different values for Chrome and IE:

element = driver.find_element_by_xpath('some_xpath')
element.location

as viewport area (where web-content displayed) sizes are different (Chrome- 1910x998, IE- 1904x965) despite of same window size. To get these values I used

driver.execute_script('return document.documentElement.clientHeight')
driver.execute_script('return document.documentElement.clientWidth')

so I tried

driver.execute_script('document.documentElement.clientHeight = "990px";')
driver.execute_script('document.documentElement.clientWeight = "1900px";')

but with no luck

So the question is how to set browser viewport size in selenium?

Answer 1

Here is function to set the viewport size:

def set_viewport_size(driver, width, height):
    window_size = driver.execute_script("""
        return [window.outerWidth - window.innerWidth + arguments[0],
          window.outerHeight - window.innerHeight + arguments[1]];
        """, width, height)
    driver.set_window_size(*window_size)

Usage :

from selenium import webdriver

driver = webdriver.Chrome()

# set the viewport size to 800 x 600
set_viewport_size(driver, 800, 600)

# display the viewport size
print driver.execute_script("return [window.innerWidth, window.innerHeight];")