MDN URL: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/month
<form>
<div>
<label for="month">What month would you like to visit us? (Summer months only, yyyy-mm)</label>
<input id="month" type="month" name="month"
min="2017-06" max="2017-09" required
pattern="[0-9]{4}-[0-9]{2}">
<span class="validity"></span>
</div>
<div>
<input type="submit" value="Submit form">
</div>
</form>
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/month#handling_browser_support
Handling browser support
compatibility with firefox
MDN Content page report details
en-us/web/html/element/input/monthI believe there's no problem in the article.
The article says that Firefox does not yet support <input type="month">:
only Chrome/Opera and Edge support it on desktop
The workaround provided (using pattern) works as intended for me in FF 86.0.1.
The compatibility information on the page is correct - Firefox does not support the month input type. You can see this by comparing FF and Chrome on the example on the page you point to. FF (the top item below) does not support the input so you have to enter text, while chrome does, so you have a date picker. I also checked bugzilla and there are open bug reports against this.

Thank @Leokuma for confirming this. Closing.
Thank You @hamishwillee & @Leokuma for the clarification. I thought using pattern I will be able to have date picker too. :cry:
Most helpful comment
Thank You @hamishwillee & @Leokuma for the clarification. I thought using pattern I will be able to have date picker too. :cry: