You can find these prefs on the about:config page to specify an external viewer/editor.

• view_source.editor.args
• view_source.editor.external
• view_source.editor.path

You can open the about:config page via the location/address bar. On the warning page, you can click "Accept the Risk and Continue" to open about:config.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Thanks for the reply Cor-el, I did the following:

view_source.editor.args  -->  view_source
   view_source.editor.external-->  true
   view_source.editor.path    --> C:\windows\notepad.exe\view_source

When i click on "page source" in Browser tools (ctrl-u) I get a page with the source code BUT, it is NOT notepad, as the pages shows colored text and I can't edit anything. Maybe the "view" in "view_source.editor.args " is wrong??

Here's how you can view and edit HTML files using Firefox (similar steps apply to other modern browsers as well):

Opening HTML files: Open Mozilla Firefox on your Windows 11 laptop. To open an HTML file from your local drive, click on the "Open File" option in the File menu. Alternatively, you can drag and drop the HTML file directly into the Firefox window.

Viewing Source Code: Once the HTML file is loaded in Firefox, you can view the source code by right-clicking anywhere on the page and selecting "View Page Source." Alternatively, you can press "Ctrl + U" on your keyboard to open the page source.

Editing HTML Code: The source code will open in a new tab as plain text. You can make changes to the HTML code directly in this tab using any text editor of your choice. For example, you can use the built-in Notepad application in Windows 11. Either you can follow this blog as reference https://pakprices.pk/

You only need:

• view_source.editor.external--> true
• view_source.editor.path --> C:\windows\notepad.exe

Leave view_source.editor.args blank (no args).

You can paste this code in the Browser Console (Ctrl+Shift+J) to check whether the path is valid.

• https://firefox-source-docs.mozilla.org/devtools-user/browser_console/

try {
  var viewSourceAppPath = Services.prefs.getComplexValue("view_source.editor.path", Ci.nsIFile);
  console.log(viewSourceAppPath.path)
} catch (ex) {Cu.reportError(ex);}

Cor-el & Hamza, thanks for replies,

I set Firefox 115.0 in win 11 as default months ago. hence all my LOCAL HTML files open in Firefox. Reset --> No args ... view_source.editor.external--> true

  view_source.editor.path    --> C:\windows\notepad.exe\view_source

The HTML code page has been showing all along, BUT it is NOT notepad and I cannot edit anything, which I already mentioned in a previous message.

Notepad shows all text in black/white , the page I get is in colored text, akin a code page in C++ .

The difference being, is what I get in Firefox in READ only.

Pasting the line in Firefox, "https://firefox-source-docs.mozilla.org/devtools-user/browser_console/" I get: a page full of RED text, on clearing I get a few text pages in black /white It does not help to get notepad to show as editor.

Having to run Visual studio (free from MS) is way over the top for something simple as editing HTML code in notepad. i might have to dust of my old Win7 laptop, alas. I like the KISS priciple

Didn't you try view_source.editor.path -> C:\windows\notepad.exe (i.e. without the \view_source) ?

Cor-el

You're my savior That works a treat