1247848 - Support window.print()

Status: RESOLVED FIXED

(Firefox for iOS :: Browser, defect)

Description

[vinoth.r]

User Agent: Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.109 Safari/537.36

Steps to reproduce:

1. Open this url  http://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_print on your Firefox in iPad or android tablet.
2. Click print this page button


Actual results:

It doesn't  open print dialogue but it does in desktop browsers, Safari for iPad and chrome for Android


Expected results:

It should promot print dialogue to print the page

Comment 1

[Aaron Train [:aaronmt]]

This doesn't work in Chrome for iOS either (WKWebView). I suspect there is no method available or no delegate method hooked up.

Comment 3

[Mark Finkle (:mfinkle) (use needinfo?)]

I'm pretty sure we don't support window.print on Android either.

Comment 4

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Attachment: PR: https://github.com/mozilla/firefox-ios/pull/1586

This patch adds support for `window.print()`. It does so by patching `window.print()` to our own handler, which sends a message to the native side of things. There we can use the standard iOS print infrastructure to print the `WKWebView`.

Comment 5

[Stephan Leroux [:sleroux]]

Comment on attachment 8725082 [details] [review]
PR: https://github.com/mozilla/firefox-ios/pull/1586

LGTM - left a comment on the PR.

Comment 6

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

There was a question in the PR about supporting the onBeforePrint/onAfterPrint callbacks.

I have been testing this and it seems that WebKit instead supports this via the 'print' media query.

var mediaQueryList = window.matchMedia('print');
mediaQueryList.addListener(function(mql) {
  if (mql.matches) {
    document.getElementById("foo").innerHTML="beforePrint";
  } else {
    document.getElementById("foo").innerHTML="afterPrint";
  }
});

Full demo at http://people.mozilla.org/~sarentz/t/onprint.html

This is triggered correctly via both this window.print() implementation and the system Print action from the Share Sheet.

So I think this is good to go in terms of WebKit compatibility.