Boolean attribute (such as 'selected') cannot be set back after reset with Firefox

[Michel (R)]

Firefox version: 18.0.2

If I use jQuery to set the 'selected' attribute on an option element, it works.

However if I reset this attribute, then the set method doesn't work anymore.

It works normally under IE (8).

The problem is in this part:

  removeAttr: function( elem, value ) {
   ...
    } else {
      elem[ propName ] = false; // <<====
    }

The set methods is something like:

set: function( elem, value, name ) {
  ...
   elem.setAttribute( !getSetAttribute && jQuery.propFix[ name ] || name, name );

Which in our case does:

   elem.setAttribute(name, name)

If elem[name] = false was called before, it doesn't work anymore under Firefox.

Apparently, the following line seems to fix the problem under this version of Firefox and IE8 but I cannot test with other browsers nor did I try other possibilities:

   elem[name] = name;

[gibson042]

Thanks for taking the time to contribute to the jQuery project! Treatment of boolean attributes has ​changed recently, and .attr and .prop can interact in non-obvious ways with respect to them, so please provide a complete reduced test case on ​jsFiddle to help us assess your ticket.

[michelgre]

Hello,

Yes I wanted to prepare a test case but it was kind of late (after midnight my time). Thank you for the fiddle link.

Here it is:

​http://jsfiddle.net/3UwC8/1/

When loaded, both options should be selected. On my Firefox 18.0.2, only the first one is.

[gibson042]

Please use .prop to update the dynamic state of elements: ​http://jsfiddle.net/3UwC8/2/

As of version 1.9, we no longer guarantee any user-visible effects of adding or removing boolean attributes, so they may vary between browsers. Also note that the ​migrate plugin both restores and warns about the old behavior: ​http://jsfiddle.net/3UwC8/3/

[michelgre]

Thanks, I see.

This code was actually part of a 3rd party jQuery UI widget, so this means that I should warn the author that his plugin should be fixed.

Thanks for the advices!