Firefox width issue

I am trying to code a mobile page, but I cannot seem to get Firefox to adjust down to 320px, which I believe is the smallest size you are supposed to develop for, right?

At first I thought the issue was with my web page, but I opened a blank tab in Firefox, and it also doesn’t go down to 320px.

In the FF Dev Tools, it appears my window is sticking at 435px. :frowning:

After you have FF Inspector open click on “Responsive Design Mode” if you need to test small page widths. It’s an icon that looks like a mobile device screen. Hover on it and the title will appear.

On the Inspector menu it is on the right side near the close X.

Or from FF Browser menu … Tools > Web Developer > Responsive Design Mode


Okay, I see it, and set it to 320 X 480.

So why is it that if I just try and drag my FF browser window I cannot go below 435px?

Can I trust that if FF’s Responsive Design Mode says 320px X 480px that is accurate and how my web page would really look on a mobile device?

The only thing you can trust is the size.

Different browsers use different rendering engines so there can be slight differences on how your page gets displayed.

iPhone (ios) safari browser uses a WebKit engine.

Google Chrome initially used the WebKit rendering engine to display web pages. In 2013, they forked the WebCore component to create their own layout engine Blink.; all Chrome variants except iOS now use Blink

Firefox comes with the stock Gecko engine.

My Firefox has a 427 Chevy Big Block, bored .40 over with Dual Quad Holley Snipers sitting on a Weiand 8-71 blower. Your page may not hold up very well. :slightly_smiling_face:


So I would have to check my web page in several browsers?

And I have heard that technically you’d have to check it on actual smartphones to really know, right?


Sweet video!

Bit late, but yes. It’s always a good idea to check phones, not specifically for responsive purposes, but because each phone has its’ own quirks and bugs. E.g. in IOS, there is a bug regarding background-attachment: fixed. Resizing your browser would not show that bug. Only an actual device (or simulator).


check ur ZOOM size of Browser or Customize your display size


Well I just broke down and got a mobile plan, so when I do responsive design for v2.0 then I can at least test on my iPhone.

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