Events Max

Enhanced cross-browser JavaScript event handling

Cross-browser event registration functions
Works correctly across multiple windows/frames/iframes
Supports both capture and bubble phases
Handlers execute in FIFO order
Implements mouseenter, mouseleave, and DOMContentLoaded events
Standardizes and supplements the event object
Correctly handles nested events

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addEventHandler()

Registers an event handler on an object.

addEventHandler(obj, type, handler[, useCapture])

obj
The DOM object listening for the event.
type
Event type. Event types are case-sensitive and should not include "on" (e.g., use "click", not "onclick").
handler
Function used to handle the event.
useCapture (optional)
If true, the handler will be executed during the capture phase. Otherwise, the bubble phase.

Returns a GUID (an integer) to identify the handler. This allows a handler to be removed by simply providing the GUID--even anonymous functions.

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removeEventHandler()

Removes an event handler that is registered on an object.

removeEventHandler(obj, type, handler_or_guid[, useCapture])

obj
The DOM object listening for the event.
type
Event type. Event types are case-sensitive and should not include "on" (e.g., use "click", not "onclick").
handler_or_guid
Either the handler itself to be removed, or the GUID of the handler.
useCapture (optional)
If true, remove the handler from the capture phase. Otherwise, remove it from the bubble phase.

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Custom mouse event attributes

evt.mouse.button
The mouse button value for mousedown, mouseup, click, and dblclick events.

This goes by the Microsoft model, where left==1, right==2, and middle==4.
In IE lte 8, the value may be incorrect on mousedown since we can't reliably keep track of the event.button value between events. (e.g., if the mouse leaves the window, buttons are changed by the user without the browser's detection, and the mouse comes back)
evt.mouse.position
Object containing the mouse positions within the screen, window, document, and layer (e.g., evt.mouse.position.document.x).

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Custom keyboard event attributes

evt.keyboard.char
Printed character or empty string
evt.keyboard.key
Key value ("Control", "Down", "Tab", "F1", etc.), printed character, or "Unidentified"

Note that these may not be correct for some special keys in Opera (notably: home, end, insert, delete, num lock, scroll lock).

Keyboard guesses

These are either the values determined above, or a "guess" derived from evt.keyCode (assuming a US English QWERTY keyboard).

evt.keyboard.charGuess
Printed character, guess based on evt.keyCode, or empty string
evt.keyboard.keyGuess
Key value ("Control", "Down", "Tab", "F1", etc.), printed character, guess based on evt.keyCode, or "Unidentified"

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Custom drag & drop event attributes

evt.draggingExternal
true if an object external to the viewport is being dragged (e.g., a file, bookmark, or browser tab)

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Additional information

There are a few custom attributes used by this script that must not be manipulated; they end with a space to make it less likely that they will be messed with:
["handlerGUID "] on handler functions
["eventHandlers "] on DOM objects that have handlers assigned to them

Be aware that browsers act differently when the DOM is manipulated. Much of it seems to have to do with when the propagation path is determined for events (e.g., as soon as they're added to the event loop vs. just before they're dispatched). Some fire mouseover/out events when an element is added/removed/positioned under the mouse, some stop bubbling an event if the currentTarget has been removed from the DOM, etc.

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General references

Techniques and inspiration largely from:

wizard04wsu/Events_Max

Events Max