1078702 - hasOwnProperty selectionStart/selectionEnd is false

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, defect)

Description

[Rob G]

Attachment: 2014-10-06 15_32_00-Edit fiddle - JSFiddle.png

User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.124 Safari/537.36

Steps to reproduce:

When attempting to detect if an input element has a selectionStart or selectionEnd property, the "hasOwnProperty" function always returns false.

I created this demo (http://jsfiddle.net/Mottie/2vwcef5x/) to show the issue. The results are the same in IE11, but in Chrome v37, all console logs return true. I don't have Safari to test the fiddle.


Actual results:

input.hasOwnProperty('selectionStart') returns false, when it should return true.


Expected results:

input.hasOwnProperty('selectionStart') should return true, just as 'selectionStart' in input returns true.

Comment 1

[Tom S. (please needinfo tschuster)]

The methods seem to be defined on input.__proto__. Probably something DOM related.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Yep. Per spec, these are accessors on the prototype.  We and IE are following the spec.  Chrome has a well-known bug where it puts some (but not all!  Try looking for "onclick" on the window and compare to looking for "onclick" on an input) properties on the wrong object.

If you're trying to do detection, you either need to check both places or use "in", which will walk the proto chain for you.