Bug 135009

Summary:	assign undefined value to Element property throws TypeError
Product:	WebKit	Reporter:	ShihChi Huang <huge.huang+webkitbug>
Component:	DOM	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED DUPLICATE
Severity:	Major	CC:	ap, ggaren, oliver, zalan
Priority:	P2
Version:	528+ (Nightly build)
Hardware:	iPhone / iPad
OS:	Other

Description ShihChi Huang 2014-07-16 22:50:14 PDT

Prior to iOS8 Safari / Safari 8.0 if we assign undefined to Element property (like document.body.scrollTop) it fallback to 0

```js
document.body.scrollTop = undefined;

TypeError: Type error
column: 110
line: 1
message: "Type error"
stack: "eval code↵eval@[native code]↵_evaluateOn↵_evaluateAndWrap↵evaluate"
__proto__: Error
```

Comment 1 Oliver Hunt 2014-07-17 17:08:11 PDT

Hmmm, this is complaining about assigning NaN (undefined is being number coerced)

Maybe due to fractional coordinates?

Comment 2 Alexey Proskuryakov 2014-07-17 17:11:46 PDT

Good point. Can you still reproduce with a current WebKit nightly? I thought that the fractional coordinate change was already undone.

Comment 3 Oliver Hunt 2014-07-17 17:13:06 PDT

I think this is a dupe of bug #134841

Comment 4 ShihChi Huang 2014-07-17 18:05:27 PDT

awesome, I cannot repro in webkit nightly r171105

Comment 5 zalan 2014-07-17 18:31:12 PDT

(In reply to comment #2)
> Good point. Can you still reproduce with a current WebKit nightly? I thought that the fractional coordinate change was already undone.

It's been reverted only for Element.scroll*. Other properties' (Element.offset*, Element.client*) return type is still double.

*** This bug has been marked as a duplicate of bug 134841 ***