Question

I tried modifying the ng-checked example so that clicking on one of the checkboxes would automatically update the other.

Clicking A, then B, then A again, is not doing what I’m expecting.

What part of the documentation should I look at to understand what’s happening ?

http://jsfiddle.net/cantcopy/ev62U/

Answer 1

Why don’t you connect both checkboxes to the same model ?

<div ng-app>
  A - Check me to check both: 
    <input type="checkbox" ng-model="master"><br/>
  B - Check me to check both:
    <input type="checkbox" ng-model="master">
</div>​

http://jsfiddle.net/ev62U/133/

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To explain your fiddle:

ng-checked does not update the model, it only updates the view (checkbox), once the expression changes.

Click A: the master is changed to true, the B checkbox is watching its ng-checked value and therefore updates the view to be checked as well.

Click B: the master2 is changed to false, the A checkbox is watching its ng-checked value and therefore updates the view to be unchecked as well.

Click A: the master is set to true and that’s not really a change as the value already was true, so it does not trigger update of B.