JQuery :: .trigger("change") Not Working For Some Reason?

I have a textbox attached to an alert which I want to fire when the textbox value is changed i .e. while the user is typing.

I attempted to use the .change() event handler unsuccessfully. After some searching I found that the .trigger("change") handler should work better but that too is not working.

My coded example is quite simple:[URL]consists of the following:

HTML
<label for="textbox1"> this should flash an alert when changed.</label>
<input type="text" id="textbox1" name="textbox1"/>

JAVASCRIPT

$('#textbox1').trigger("change", function() {
alert("Changed");
});

I have other jquery / ajax elements on the page that work fine onblur (select boxes) but I really want the textbox to fire on change.