Bug 226725 – MouseEvent.constructor misses checking if the param value is non-infinite or not

• Status: RESOLVED
• Resolution: WONTFIX
• Component: WebKit Misc.

[[e-mail]]

Steps to reproduce:

(1) Open a tab and navigate to any URL;
(2) Run the following code in the Console of Devtools:
```
new MouseEvent('',{screenX: NaN});
```
(3) This code would be evaluated successfully without any exceptions thrown.

Actual results:

This code would be evaluated successfully without any exceptions thrown.

Expected results:

In Chome, this code would throw an exception: `Uncaught TypeError: Failed to construct 'MouseEvent': The provided double value is non-finite.`.
It seems reasonable to throw such an exception since the type of the screenX param is double.

[[e-mail]]

As https://docs.w3cub.com/dom/mouseevent/screenx says, screenX is `A double floating point value. Early versions of the spec defined this as an integer referring to the number of pixels`.

[Sam Weinig]

Looks like the latest version of UIEvents still has this as a long:

https://w3c.github.io/uievents/#idl-mouseeventinit.

[Chris Dumez]

(In reply to Sam Weinig from comment #2)
> Looks like the latest version of UIEvents still has this as a long:
> 
> https://w3c.github.io/uievents/#idl-mouseeventinit.

Indeed, we are matching the specification and Firefox. Maybe this a bug should be filed against Chrome? They are the only ones not aligned here.

[Radar WebKit Bug Importer]

<rdar://problem/79282818>

[Chris Dumez]

We are aligned with Firefox and the specification here. I don't think we should make this change for now.