Any browser that does not support the touch events by the end of 2010 is out of the race.

• Even multitouch Android supports only one touch at a time.
• Dolfin supports multitouch (i.e. you can read out several touches at once) but only up to a point. My multitouch drag-and-drop doesn’t work in this browser.

The zoom event doesn’t yet exist. Some browsers fire the resize event instead.

Context menus that pop up ontouchhold do not exist on some Operas, Symbian, Palm, Dolfin, and Firefox. Thus the contextmenu event should not fire in those browsers.

• The contextmenu event does not fire in Opera, iPhone, Android, MicroB, and NetFront when a context menu appears.
• Opera, Symbian, Palm, Firefox, MicroB, and NetFront do not fire any event when the user zooms.
• Palm, Samsung, Firefox, IE, and NetFront do not fire scroll events. Opera does, but is unreliable.
• iPhone and Symbian don’t fire the click event when a mouseover or mousemove event causes a DOM change. I don’t rule out that this may actually be a wise decsion for “fixed web” sites, but the click event is more important than the legacy events and my gut feeling is they shouldn’t do this regardless
• BlackBerry only fires a click on links.
• Dolfin always fires contextmenu and scroll events, even when they’re not necessary.

This is how it all works:

1. If a touchstart and a touchend event occur on (roughly) the same coordinates this constitutes a mobile click action. The legacy events are fired, as is the click event.
2. The legacy events to be fired are mouseover, mousemove, mousedown, and mouseup. In addition the :hover styles, if any, are applied to the element.
3. Only one mousemove event fires.
4. When a mobile click action occurs on another element, the mouseout event is fired on the original element and the :hover styles are removed.
5. The dblclick event is not supported. (It’s totally useless, anyway.)

Of course, browsers may disagree on the finer points.

• iPhone and Symbian: see interface events.
• BlackBerry and NetFront do not support the mouseover and mousemove events.
• Palm, Samsung and Firefox do not support the mousemove event.
• Both Vodafone Widget Managers (the Opera-based Symbian one and the WebKit-based Samsung one) fire a mousedown event when the user first touches the screen and a continuous series of mousemove event when he moves his finger. In theory this makes a drag-and-drop script possible. Performance is lousy, though, and you should not attempt to use this feature.
• BlackBerry only fires these events on links.

• BlackBerry only fires click events on links.

Should fire when a context menu appears. This usually happens after a touch-and-hold action. In general links have context menus, other areas don’t.

• Dolfin always fires the contextmenu when you touchhold the screen, even though it doesn’t actually have a context menu.

An event should fire when the user zooms. Some browsers use the resize event, but that is not correct. They should fire the zoom event instead.

• The resize event sometimes fires in Iris, but not when you’d expect it.

Should fire when the browser scrolls. It’s not unusual that this event also fires while zooming, since a double-tap or pinch zoom action can easily cause a bit of scrolling.

• Operas fire far too few scroll events (mostly during resize) and are unreliable.
• Dolfin always fires a scroll event when the user drags his finger, whether any scrolling occurs or not.

The touchstart event is the standard, but a mousedown that fires when the user starts the touch action is OK, I suppose.

There should be a touchmove event that fires continuously while the user drags his finger across the screen.