Button convention

All objects of type function can be bound to a button element.

<button data-name="save">Save</button>

The convention will also look for a function guard member on the ViewModel which by convention is prefixed with can

TestViewModel = function() {
    var self = this;
    this.save = function() {
        self.canSave(false);
    };
    this.canSave = ko.observable(true);    
};

http://jsfiddle.net/3Ajnj/