Related to a recent question made to my VBA – Open a URL in FireFox/Chrome article and out of curiosity, I decided to figure out how one could determine which Web Browser was defined as the default web browser for a PC.

The Common Approach

I went out digging and the information I was finding simply didn’t work when I tested it. Some posts were mentioning checking the

HKEY_CLASSES_ROOT\http\shell\open\command\

and/or

HKEY_CLASSES_ROOT\https\shell\open\command\

registry key(s).

Some mentioned checking

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.html\UserChoice

but as I said, the returned values didn’t match my settings when I’d make changes to my default app.

So I kept digging.

My Solution to Find the Default Web Browser

So what is one to do then?

I decided to profile my PC while I made changes to my Default Apps. From the data collected, I was able to determine that the actual registry key of interest was

HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Associations\UrlAssociations\https\UserChoice\ProgId

from there, it then just became a question of building a wrapper function to read the value, cross reference that value to isolate the actual exe filename.

Below is my solution to identifying the default web browser on a PC:

'---------------------------------------------------------------------------------------
' Procedure : GetDefaultBrowser
' Author    : Daniel Pineault, CARDA Consultants Inc.
' Website   : http://www.cardaconsultants.com
' Purpose   : Returns the name of the System's Default Web Browser
' Copyright : The following is release as Attribution-ShareAlike 4.0 International
'             (CC BY-SA 4.0) - https://creativecommons.org/licenses/by-sa/4.0/
' Req'd Refs: Uses Late Binding, so none required
'
' Usage:
' ~~~~~~
' GetDefaultBrowser()
'   -> msedge, firefox, brave, iexplore, ...
'
' Revision History:
' Rev       Date(yyyy/mm/dd)        Description
' **************************************************************************************
' 1         2020-12-14              Initial Release
'---------------------------------------------------------------------------------------
Function GetDefaultBrowser() As String
    Dim oShell                As Object
    Dim sProgId               As String
    Dim sCommand              As String
    Dim aCommand              As Variant

    On Error GoTo Error_Handler

    Set oShell = CreateObject("WScript.Shell")
    'Default ProgId
    sProgId = oShell.RegRead("HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Associations" & _
                             "\UrlAssociations\https\UserChoice\ProgId")
    'Cross-reference the sProgId to get the exe associated with it
    sCommand = oShell.RegRead("HKEY_CLASSES_ROOT\" & sProgId & "\shell\open\command\")
    'Parse the returned value to extract just the exe filename
    aCommand = Split(sCommand, Chr(34))
    GetDefaultBrowser = Right(aCommand(1), Len(aCommand(1)) - InStrRev(aCommand(1), "\"))    ' firefox.exe
    'Trim off the exe and only return the filename
    GetDefaultBrowser = Left(GetDefaultBrowser, InStr(GetDefaultBrowser, ".") - 1)    'firefox

Error_Handler_Exit:
    On Error Resume Next
    If Not oShell Is Nothing Then Set oShell = Nothing
    Exit Function

Error_Handler:
    MsgBox "The following error has occurred" & vbCrLf & vbCrLf & _
           "Error Number: " & Err.Number & vbCrLf & _
           "Error Source: GetDefaultBrowser" & vbCrLf & _
           "Error Description: " & Err.Description & _
           Switch(Erl = 0, "", Erl <> 0, vbCrLf & "Line No: " & Erl) _
           , vbOKOnly + vbCritical, "An Error has Occurred!"
    Resume Error_Handler_Exit
End Function

Once again, the above code uses Late Binding techniques and has no application specific dependencies making it fully portable.