How do I access the Ember.checkbox object?

I have an input type=checkbox element as such:

{{input type="checkbox" id="theCheckbox" name="theCheckbox" checked=isChecked click=(action 'checkboxAlert' value="target.checked")}}

How do I get the Ember.checkbox object in the JS file so that I can toggleProperty for the value of checked? I have the following in my JS checkboxAlert action code but it's not working as I think I'm not correctly referencing the object.

theCheckbox.toggleProperty('checked');