Events

function addListener(elem, type, fn, capturingPhase) {
    if (elem.addEventListener) {
        elem.addEventListener(type, fn, capturingPhase);
    } else if (elem.attachEvent) { // IE8...IE6. Bubbling only
        elem.attachEvent("on" + type, function() { return fn.call(elem, window.event); });
    } else { // IE5-. Bubbling only
        elem["on" + type] = fn;
    }
}

Functions and Properties of Event Object.

Name	Description	Returns
type	To specify the name of the event.(i.e click, mouseout)	string
target	The element at which the event is to be triggered	HTMLElement
currentTarget	Current element whose event listeners are currently being invoked.	HTMLElement
eventPhase	The phase in the life cycle of an event.	number
bubbles	A true value is returned if the event will bubble through the document, or else a false is returned.	boolean
cancelable	A true value is returned if the event has a default action that can be cancelled, otherwise a false is returned.	boolean
timeStamp	To denote the time at which the event was created, if no time is available then 0 is returned.	string
stopPropogation()	To cancel any further event capturing or event bubbling. Can be used if bubbles is true.	void
stopImmediatePropogation()	It cancels any further event capturing or event bubbling and prevents any other event handlers from being called.	void
preventDefault()	It prevents the browser from performing the default action associated with the event	void
defaultPrevented	A true value is returned if the preventDefault() has been called.	boolean