Using Firefox (and IE) to debug your apps in Visual Studio

The demand for Firefox is rising. If I may repeat my favourite feature: increasing and descreasing fornt size with ^+ and ^- is a delight for my eyes. Almost saves me from a new pair of glasses. It would be nice to start using FF in Visual Studio when building the app. Which is not that difficult but took some searching. Let me share with you how to set up FF in VS (2003).

  • In the file menu is a “browse with“ option. Select this.
  • Add Firefox to the list of supported browser and check “default“

In the options of your project set “always use IE“ to false

  • That’s all.

    Now FF wil be the default browser when you launch your app from VS. Breakpoints and everything work as usual. When your project leans heavely on IE, for instance because you don’t want to miss smart navigation, you can instruct VS to keep using IE on a project basis. When you drop IE you also drop the possibility for remote debugging. But that’s something I had already given up.


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    • ASP.Net


      Your post was very interesting. Thanks for providing a great help . I appreciate with you.

    • great

      Nice information thanks

    • Rytis Usalis

      Hello, thank you for help.

    • Mark Kamoski

      How can one set VisualStudio 2008 to end debugging when the FireFox window closes? This works for IE8 but not for FF3.6 now. In IE, if I am running in debug mode, and I have a browser open with my web page in it, all is well, and if I close that IE window being debugged then the VisualStudio debugging also stops. However, in FireFox, if I close the FireFox window being debugged, then the debugging in VisualStudio does not close. Any ideas? Please advise. Thank you. — Mark Kamoski

    • Rick O’Shay

      The plus/minus font control is nice, but I personally like their FireBug javascript debugger. Then again, if you’re using Microsoft’s Ajax kit it isn’t with shit, because of the confusing morass Microsoft generates. I’m hoping that in 5 or 10 years they come up with a good JS debugger on their own. I’m encouraged that they recently introduced the 10-year-old technology known as MVC and that by 2020 they will have an IoC container.

      (what a horrific company for developers they are)

    • Paulie

      I debug in Firefox by browsing to the page in FF, setting my breakpoint(s) and then in VS (2008) selecting the Menu option Debug -> Attach to Process and then selecting w3wp.exe (the IIS application pool process) – if you don’t see this process you may have to ensure ‘Show processes in all sessions’ is checked. Hope this helps!

    • john

      Thank you.

    • Noelia
    • Noelia

      I have VS 2005 and my applications run in Firefox. I would like to debug it in IExplorer nad i don’t know to change it because VS 2005 haven’t “browse with“ option and “always use IE“ property in the project.
      How can i do it?Thanks

    • Roger

      Wow ! at least ! I use firefox as my default browser but I wanted to use IE for debug, but it was impossible till now to find on internet how to stop vs to launch firefox when I started to debug my site. THANKS

    • Jovi

      If firefox detaches, click on disable script debugging in the advanced tab of internet options in IE.

    • Phi Nguyen

      There is an option in Firefox that let you open a new browser window if links are from other apps. This would let you use Firefox as both your regular browser and for debugging as well

    • Sham


    • Sarelj

      Re: the firefox and postback problem. Thanks for that tip… It did not help but made me think. You are right, it is a browser problem and not a server proble. I do have cookies enabled for all sites. Where do I disable sessions in FF?? I still think that it might be something else??

    • pvanooijen

      IsPostBack is a server-side feature. I don’t think your problem has to do with FF itself, but rather by it’s settings. Did you disable session, cokkies or something like that ?

    • Sarel j

      I know that this is off topic but could someone please help me? I have 2 datagrids:dgModels and dgFavorites. The idea is that all the models that you select should be added to dgFavorites on postback.

      This works great with IE but Firefox does not recognize the postback??? The isPostback does not register in Firefox.

      Please help!!

    • Nazmundo

      xlnt tip peter thanks …. couple this with the
      web developer extension and were all on our way to creating accessible standards compliant web apps! (well almost)

    • aaaa

      thanks for help – my vs 2005 beta lunched firefox but I wanted to check how it looks in IE. It worked :)

    • Shane Henderson

      If you want breakpoints and stepping through code to work with Firefox you have to close all instances of Firefox before you run in debug mode. Then when you debug a web application through VS.NET and it launches a window everything will work. If you have any other browser instances of Firefox open VS will not attach to the process.

    • Les Matheson

      It does seem that the “Browse with…” option isn’t always on the File menu — on my VS 2003, it shows up if I right-click a .aspx file in Solution Explorer. Its also available in the large list of functions in the File section of /Tools /Customize /Commands.

    • Thomas

      I tried this as well. I went up to “File” > “Browse With”, and gave it a shot.

      Hitting the Debug button caused Visual Studio to start up FireFox with my app loaded. However, as soon as it does this, the debugger stops.

      One interesting sidenote. After doing the above, I noticed the “Browse With” command had mysteriously been removed from my “File” menu. WTF? I used the suggestion in the previous comments to add it back to the menu.


    • Micke

      FF debugging works fine for me. Can trace into code, use break points …

      Using FireFox 1.0.1

    • Peter van Ooijen

      Hi Tim,

      have you read ?

      When the app has started use "Attach to process" <ctrl><Alt>P

    • Tim Haines

      This doesn’t work for me either. I have the same problem as Andre. When Firefox starts the debugger quits. It probably just needs tweaking in some small way – pass as to what it might be though.

    • Scott Elkin
    • Peter van Ooijen
    • spakinz

      i don’t have the option ‘browse with..’. Which version of vs 2003 do you have?

    • Peter’s Gekko

      Debugging a webservice with Firefox

    • andre


      I was so happy for a minute…

      I just noticed that it was iE that had launched. FF still has same problem. Debugger unloads as soon as FF is launched. :(

      Still hoping for a solution….

    • andre

      CORRECTION…to last post.

      The debugger immediately unloads when trying to debug a Web Service usig FF as browser. WEb Applications DEBUG FINE! Peter your my hero of the day…

    • andre

      I have been trying to do this ever since I left Vs 6 behind. Unfortunately, even after trying these suggestions, I still cannot use FF or Moz to debug VS.NET. When debugging, as soon as FF starts up the debugger immediately unloads. Any ideas?

    • Raterus

      I had to add "Browse With" to my File menu through the following

      Tools | Customize | Commands Tab

    • Ben

      THIS IS THE GREATEST TIP EVER. It also stops your code from going to read only…

    • WheelThis

      You should try CTRL+Wheel to increase/decrease the font size.

      That will be your favorite feature