Check if event is triggered by a human

I think that the only way to do this would be to pass in an additional parameter on the trigger call as per the documentation.

$('.checkbox').change(function(e, isTriggered){
  if (!isTriggered)
  {
    alert ('human');
  }
});

$('.checkbox').trigger('change', [true]); //doesn't alert

Example: http://jsfiddle.net/wG2KY/

More straight forward than above would be:

$('.checkbox').change(function(e){
  if (e.isTrigger)
  {
    alert ('not a human');
  }
});

$('.checkbox').trigger('change'); //doesn't alert

Currently most of browsers support event.isTrusted:

if (e.isTrusted) {
  /* The event is trusted: event was generated by a user action */
} else {
  /* The event is not trusted */
}

From docs:

The isTrusted read-only property of the Event interface is a Boolean that is true when the event was generated by a user action, and false when the event was created or modified by a script or dispatched via EventTarget.dispatchEvent().

You can check e.originalEvent: if it's defined the click is human:

Look at the fiddle http://jsfiddle.net/Uf8Wv/

$('.checkbox').change(function(e){
  if (e.originalEvent !== undefined)
  {
    alert ('human');
  }
});

my example in the fiddle:

<input type='checkbox' id='try' >try
<button id='click'>Click</button>

$("#try").click(function(event) {
    if (event.originalEvent === undefined) {
        alert('not human')
    } else {
        alert(' human');
    }


});

$('#click').click(function(event) {
    $("#try").click();
});