gistfile1.js

ko.bindingHandlers.btnClick = {
    init: function (element, valueAccessor, allBindings, viewModel, bindingContext) {
        var wrappedValueAccessor = function () {
                return function (data, event) {
                    var txt = $(element).text();
                    $(element).text("Please Wait...");
                    valueAccessor().call(viewModel, data, event);
                    $(element).text(txt);
                };
        };
        ko.bindingHandlers.click.init(element, wrappedValueAccessor, allBindings, viewModel, bindingContext);
    },
    update: ko.bindingHandlers.click.update
};