Why are you looking at .isTrigger? It is not documented. Do not use it.

IE doesn't fire a change event when you click a checkbox. We have to fire one for you.

I was looking at it in order to check whether the event was caused by a manual .trigger() or was a user interaction consequence.

Now I'm using !!evt.originalEvent in order to create a flag where to check if it's native user interaction or not.

What method would you recommend?

Replying to [comment:1 dmethvin]:

Why are you looking at .isTrigger? It is not documented. Do not use it. IE doesn't fire a change event when you click a checkbox. We have to fire one for you.

By the way, it's pretty interesting that a lot of users are using that .isTrigger to check what I wanted. You can check out at most used knowledge bases such as Stack Overflow.

So this ticket is useful for whoever finds it, it's a write down of what's happening. We should not use undocumented methods/properties/etc.

When you trigger an event manually you can pass data, so you could do something like this:

$("#checkbox").on("change", function( event, mydata ) {
    if ( mydata ) {
       console.log("called by trigger");
    }
    else {
       console.log("NOT called by trigger");
    }
});
$("#checkbox").trigger("change", [ true ]);

http://jsfiddle.net/gy4LH/

By the way, it's pretty interesting that a lot of users are using that .isTrigger to check what I wanted. You can check out at most used knowledge bases such as Stack Overflow.

If it's not documented, it may break in the future.

BTW I highly do not recommend using custom data in events to check if it's user event or not, since not all implementations across jQuery developers are using that. So there's no guarantee that anyone won't trigger without that useful relying-onto data.