python's webbrowser launches IE, instead of default browser, on Windows relative path

You can use get(name) to use a specific browser.

You’ll need to register the Chrome webbrowser, as it doesn’t seem to be one of the predefined browser types, and then you should be able to do this:

webbrowser.get('chrome').open('http://www.google.com')

Update:

Actually, you might be able to just one of the following:

webbrowser.get('windows-default').open('http://www.google.com')
webbrowser.get('macosx').open('http://www.google.com')

The docs show no predefined defaults for Linux.

Looking at the module source code, it first tries to use the Windows default browser but if it doesn’t work, it searches for common browser names that are commands, ie. that are in the PATH variable. Try adding the location of your web browser to your PATH.

The webbrowser module is supposed to use the default browser, so this might be a bug. On the other hand, use this explanation from the docs to troubleshoot your problem:

If the environment variable BROWSER
exists, it is interpreted to override
the platform default list of browsers,
as a os.pathsep-separated list of
browsers to try in order. When the
value of a list part contains the
string %s, then it is interpreted as a
literal browser command line to be
used with the argument URL substituted
for %s; if the part does not contain
%s, it is simply interpreted as the
name of the browser to launch.

I have the same problem with firefox. http://www.google.com is opened in ff while file:///test.html is opened in IE.

webbrowser doc says:

Note that on some platforms, trying to
open a filename using this function,
may work and start the operating
system’s associated program. However,
this is neither supported nor
portable.

This problem appears for me only with file:/// protocol URLs, which are probably not registered to chrome, so os.startfile() (which is the first thing webbrowser.open tries on Windows) opens them in Internet Explorer. I don’t think putting your other browser in the PATH will help, since os.startfile() still gets invoked before even trying the browsers in the path.

What you can do, is to check the default browser for http:// in the registry (for instance, by checking the registry key HKEY_CLASSES_ROOThttpshellopencommand) and use that one for file:/// URLs. Not pretty, but it should work.

import _winreg
import webbrowser
import shlex
import subprocess

def win_browser_open(url):
    if url.startswith('file:///'):
        browser = _winreg.QueryValue(_winreg.HKEY_CLASSES_ROOT, r'httpshellopencommand')
        browser = browser.replace('%1', url)
        subprocess.Popen(shlex.split(browser))
    else:
        webbrowser.open(url)

This opened a new Chrome tab for me, and it’s still OS-independent:

webbrowser.get().open('http://www.google.com')

What’s odd is that without the get() call, it still uses IE. This looks like a bug with a simple workaround.

Using Windows 10, in short, everything that does not include a full URL in the https://example.com format is opened in IE for me. For example, if I say

webbrowser.open("https://www.example.com")

it will open a new tab in Chrome, while

webbrowser.open("example.com")

will open IE. Any .get() will cause it to not open a browser at all.

Kind of weird behaviour, but I can see that this is a complex thing do implement and likely the OS is to blame for this behavior.

What worked for me with Python 3.6, Windows 10, was using the register() function with BackgroundBrowser, to sign in my desired browser:

import webbrowser

# Register your preferable browser
browser_path = 'C:/path/to/opera.exe'
webbrowser.register('opera', None, webbrowser.BackgroundBrowser(browser_path))

# Get an instance and launch your file
browser = webbrowser.get('opera') 
browser.open('html_file')

Bonus observation –

webbrowser also has a GenericBrowser class.

Looking at the source, seems BackgroundBrowser uses start_new_session when calling subprocess.Popen(), whereas GenericBrowser does not.

I’m not aware of that flag’s exact functionality.

Practically however, using BackgroundBrowser switches to the browser window, while GenericBrowser just opens the tab, but doesn’t switch.

Use this:

import webbrowser
webbrowser.get('windows-default').open('http://www.google.com')

since all answers did not solve this/my issue, this way worked for me… (windows)

commands needs to be in a list, not in a single string! (in this case, "start", "filepath"), also shell needs to be True (windows)

import subprocess
subprocess.Popen(['start', 'C:/Users/User/Desktop/convert_report.html'], shell=True)

It seems that webbrowser module couldn’t find filename in cwd because you opened the program by shortcut or terminal, so cwd is different from the program’s directory.

In that case, you have to convert the path into the absolute path of the program’s directory when giving a path to webbrowser.open function.

The program’s path is stored as __file__ global constant.

You can fix like that:

webbrowser.open(os.path.join(__file__, '..', filename))

I fixed the same problem by this solution.

Add a BROWSER variable to your system variables and put path of your default browser.

I just had the same issue of web pages suddenly opening with Internet Explorer, which only started after installing Visual Studio 2017. My guess is that VS2017 installed its own version of IE.
My program was opening websites using webbrowser.open(url), but I had stripped the ‘https://’ protocol from the beginning of each URL. Now, by making sure that all URLs have the ‘https://’ protocol at the beginning, the issue goes away and the pages are once again opened in Chrome (my Windows default browser).