Exclamation mark doesn't work in trigger() when using event namespace in jQuery 1.9

user2301368

Here is the code:

$("div").on("click",function(){
       console.log("click");
});
$("div").on("click.plugin", function(){
       console.log("click.plugin");
});
$("button").click(function() {
      $("div").trigger("click!");    
});

and the HTML:

<div>test.</div>
<button >Trigger event according to namespace</button>

When I run the code under jQuery 1.8.3, it works. When I click button, it logs click in the console.

But when I change to jQuery 1.9.1, nothing happens when I press the button. It seems like the exclamation mark doesn’t work anymore in 1.9.1.

I can’t find this change in the 1.9 upgrade guide. Does anybody know why?