1506141 - Invalid <input type="number"> contents get cleared when frames are reconstructed (e.g. due to change in 'position' or 'display' property)

Status: NEW

(Core :: Layout: Form Controls, defect, P3)

Description

[Daniel]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:63.0) Gecko/20100101 Firefox/63.0

Steps to reproduce:

While an input[type=number] is filled with an invalid content, change its CSS positioning (or one of its parents).

I've created a JSFiddle to demonstrate the issue: https://jsfiddle.net/xpvt214o/932288/


Actual results:

The input clears itself.


Expected results:

The invalid content should be left untouched in the input (at least from I've understood from #1398528).

Comment 1

[Daniel Holbert [:dholbert]]

Thanks for the report! The CSS "position" change here is one of many things that triggers frame reconstruction (rebuilding the layout boxes associate with this element).

Frame reconstruction is not really intended to have web/user-visible side effects, so this is indeed unintentional.

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

Here's a copy of the testcase (using :hover rather than script for the style tweak), so that we're not dependent on jsfiddle for testing/archival here.