About HTML5's new feature placeholder on Firefox

Question

On Firefox:

console.log(document.createElement('input').placeholder === ''); // true

console.log(document.createElement('input').hasOwnProperty('placeholder')); // false

I think the 2nd line codes should return true just like what you can see on Chrome. But I get false. Why?

Thank you!

Answer 1

The spec defines the JS property as being on the prototype, not on the object itself. Chrome gets this wrong for all DOM properties; it's a longstanding bug in Chrome.