IT:AD:Durandal.JS:HowTo:Conditional Anchor CLicks
Summary
As per good UX design patterns, Buttons are good for Primary Actions. Anchors are better for Secondary Actions.
If the Action is a Conditional Navigation, you need to perform logic before navigating to a destination, or cancelling the navigation and showing an error message.
Process
<a data-bind="click: goToMyLink">Go</a>
goToMyLink: function() { //decide what to do...then: location.assign('myLink.php'): }