click F11

Hi, you need this attribute on your iframe:

allowfullscreen="true"

(or just allowfullscreen without an assigned value)

Ref. https://developer.mozilla.org/docs/Web/HTML/Element/iframe#Attributes

My first reply assumed it was your web page to modify. If it isn't your web page, you can try modifying the iframe element using a script (such as a bookmarklet or user script), or there might be an extension that can do it. If there is an extension, it may refer to enabling video full screen instead of PDF full screen since this problem is more often observed with embedded videos.

Thanks a lot for the quick responses of both of you.

@FFUs3r: Clicking F11 will open Firefox in the full screen mode but not an embedded PDF so does not achieve my goal.

@jscher2000: You assumed correctly that I am not able to change the iframes. Since I do not have much experience and not the capacity at the moment to go about writing a script for that I would most likely have to switch browsers in those cases, which I wanted to avoid.

Does anyone know if I can download an extension that can open embedded pdfs in Full screen mode? I am just surprised that this option exists in the regular PDF view in Firefox but doesn't in the embedded version.

Hi J.Heindel, you may have seen this issue with embedded videos on some sites; same problem. Embedded content is not allowed to go full screen without the allowfullscreen attribute set.

As a temporary workaround, you can right-click the PDF, expand This Frame, and choose Open Frame in New Tab.

As an example of a script to modify the embed, this one finds every iframe in a page, sets it to allowfullscreen="true", and reloads its contents so the PDF viewer recognizes the change. I wish I had a way to limit it to PDFs so that other frames aren't affected, but that could be tricky because, as in this case, you can't always tell from the file name.

var fr=document.getElementsByTagName('iframe'); 
for(var i=0;i<fr.length;i++){
  fr[i].setAttribute('allowfullscreen','true'); 
  fr[i].contentWindow.location.reload();
}

Hopefully I can think of (or you can find) a better way.

Hi Jscher2000,

the right click --> new tab option is a reasonable work around for me for now - so thanks a lot.

Thank you also for the script, but I would have to read up on some more details on how to run it correctly plus the side-effects you mentioned.

Thanks a lot!