Document that addClass and removeClass change the property

[AurelioDeRosa]

Fixes gh-312

[AurelioDeRosa]

@agcolom @kswedberg Fixed! Thank you for the feedback.

[arthurvr]

I wonder if it makes sense to also mention which property we're actually talking about, instead of just "the property"

[kswedberg]

@arthurvr, @AurelioDeRosa: 👍 to specifying the property. Maybe something like this?…

The .addClass() method manipulates the className property of the selected elements, not the class attribute. Once the property is changed, it's the browser that updates the attribute accordingly.

[gibson042]

Note also that behavior will change in jQuery 3.0, where we will set the class attribute instead of the className property for better SVG support: jquery/jquery#2199

[AurelioDeRosa]

PR updated. @gibson042 I'll open a separate issue for that and create a different PR if you agree. This way we can merge it into the relevant branch.

[gibson042]

👍

[AurelioDeRosa]

Anyone keen for a final review of this?

[dmethvin]

LGTM, and we will revisit it when 3.0 lands.