attr should return an empty string, not undefined per DOM spec.

[rpflorence@…]

Incorrect 1.6 behavior: ​http://jsfiddle.net/rpflorence/PzRya/

Correct 1.5 behavior: ​http://jsfiddle.net/rpflorence/PzRya/1/

Spec: ​http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-666EE0F9

Returning an empty string is

1. still falsey, so you can still if (attr),
2. follows the spec, and
3. is the previous behavior.

[Timmy Willison]

We are following spec exactly now actually. There is no title attribute on that element.

[rpflorence]

Replying to timmywil:

We are following spec exactly now actually. There is no title attribute on that element.

Actually, now that I read the spec closer, it's impossible to "follow it exactly" because it isn't clear for this use case, where the attribute doesn't exist.

From the spec:

Return Value DOMString

The Attr value as a string, or the empty string if that attribute does not have a specified or default value."

I can respect the change to mimic the browsers' behavior, but claiming spec compliance isn't a valid reason for this API change. Returning an empty string is, in my opinion, more useful.

[dmethvin]

To get an empty string you can use the property, available through .prop('title'). There is no title attribute in the markup so the browser is justifiably returning null for the .getAttribute('title') method call and therefore we are returning undefined.