1841756 - Mouse Event listeners are not triggered for mouse4 and mouse5 buttons

Status: NEW

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[patrickmzimmermann]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/114.0

Steps to reproduce:

Create a mouse listener on a page or directly in the console, for example: window.addEventListener("mousedown", e => console.log(e))

Actual results:

event is triggered for left, right and middle mouse buttons, but it does not trigger for mouse 4 and mouse 5 (back and forward buttons)

Expected results:

The event should trigger with specific values as seen here: https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button#value

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::DOM: UI Events & Focus Handling' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[patrickmzimmermann]

Any ETA of when this could be fixed? I desperately need it for some custom extensions.

Comment 3

[ZOM]

Even Mozilla's own documentation says this is supposed to capture mouse 4 and 5, and yet it doesn't. Chrome and Edge do it just fine, but Firefox not.

A number representing a given button:

0: Main button, usually the left button or the un-initialized state
1: Auxiliary button, usually the wheel button or the middle button (if present)
2: Secondary button, usually the right button
**3: Fourth button, typically the Browser Back button**
**4: Fifth button, typically the Browser Forward button**

https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/button#value

WHY IS THIS STILL NOT FIXED?! This issue is >2 years old!

Comment 5

[Connor]

From my testing mouse6, 7, ... up to mouse11 also don't appear to be detected. While the w3 standard (https://w3c.github.io/uievents/#dom-mouseevent-button) only explicitly mentions five values that must be handled, it doesn't exclude the possibility of values above 4 being used (any value above 2 as well as values below 0 are stated as being usable). Indeed, MouseEvent.buttons represents a 16-bit field for simultaneous button states, implying that up to sixteen distinct mouse buttons could be supported.

Is the intended fix to this to support these higher buttons as well, or only up to the fifth?