675399 - JavaScript weirdness / interpretation difference between Firefox and other browsers involving document.write inside setInterval call

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[Tobias (:Tobbi) Markus]

Attachment: testcase

This literally is the reason why I'm still in the office, although it being off working hours...

Calling document.write inside a setInterval call doesn't continously add a's to the page, as expected.

It works in Google Chrome and Safari as expected.

This is the JS code:
function increment() { document.write("a");}
var ID = document.addEventListener("DOMContentLoaded", function() { window.setInterval("increment();", 1000); });

Comment 1

[Boris Zbarsky [:bzbarsky]]

You're calling document.write() after parsing is done.  Per http://www.whatwg.org/specs/web-apps/current-work/multipage/content-models.html#dom-document-write step 3, this triggers a call to open().

Then http://www.whatwg.org/specs/web-apps/current-work/multipage/content-models.html#dom-document-open step 12 replaces the window associated with the document with a new window.  The list of timeouts is attached to the old window, so goes away.

WebKit just gets this wrong.  Please report the problem to them....

Comment 2

[Boris Zbarsky [:bzbarsky]]

Opera gets this right too.

Comment 3

[Tobias (:Tobbi) Markus]

Alright, thanks for the clarification!