lib/Ext/field/Checkbox.js
function(e) {
        var me = this,
            oldChecked = me._checked,
            newChecked = me.getChecked();

        // only fire the event when the value changes
        if (oldChecked != newChecked) {
            if (newChecked) {
                me.fireEvent('check', me, e);
            } else {
                me.fireEvent('uncheck', me, e);
            }

            me.fireEvent('change', me, newChecked, oldChecked);
        }
    }
function(e) {
        var me = this,
            oldChecked = me._checked,
            newChecked = me.getChecked();

        // only fire the event when the value changes
        if (oldChecked != newChecked) {
            if (newChecked) {
                me.fireEvent('check', me, e);
            } else {
                me.fireEvent('uncheck', me, e);
            }

            me.fireEvent('change', me, newChecked, oldChecked);
        }
    }
Fires the `check` or `uncheck` event when the checked value of this component changes.
@private