gistfile1.js

ko.bindingHandlers.hasFocus = {
    init: function(element, valueAccessor) {
        $(element).focus(function() {            
            var value = valueAccessor();
            value(true);
        });
        $(element).blur(function() {
            var value = valueAccessor();
            value(false);
        });           
    }
};

ko.bindingHandlers.fadeVisible = {
    init: function (element, valueAccessor) {
        // Initially set the element to be instantly visible/hidden depending on the value
        var value = valueAccessor();
        $(element).toggle(ko.utils.unwrapObservable(value)); // Use "unwrapObservable" so we can handle values that may or may not be observable
    },
    update: function (element, valueAccessor) {
        // Whenever the value subsequently changes, slowly fade the element in or out
        var value = valueAccessor();
        ko.utils.unwrapObservable(value) ? $(element).fadeIn() : $(element).fadeOut();
    }
};