if (W3C/Netscape) {
use W3C/Netscape model for access and property names
}
else if (Explorer) {
use Microsoft model for access and property names
}

function doSomething(e) {
// e gives access to the event
}

element.onclick = doSomething;

function doSomething() {
// window.event gives access to the event
}

element.onclick = function () {alert('Event type is ' + window.event.type)}

element.onclick = doSomething;

function doSomething(e) {
if (!e) var e = window.event;
// e gives access to the event in all browsers
}

<pre onclick="doSomething(event)">

function doSomething(e) {
alert(e.type);
}