Solution 1:

Because IE and Chrome put the event in the global object window, so you can get it. In firefox, you need to let the first parameter be the event.

function dayBind(event, xyzValue) {
    var e=event || window.event;
    if(event.type == 'click')
       alert('Mouse Clicked')
}

Solution 2:

If you're setting up the handler with an "onclick" attribute or something (which, since you tagged the question "jQuery", you really should consider not doing), you have to explicitly pass it:

<button type=button onclick='whatever(event)'>Click Me</button>