filebrowser-durandal-widget/lib/knockout/src/binding/defaultBindings/submit.js

ko.bindingHandlers['submit'] = {
    'init': function (element, valueAccessor, allBindings, viewModel, bindingContext) {
        if (typeof valueAccessor() != "function")
            throw new Error("The value for a submit binding must be a function");
        ko.utils.registerEventHandler(element, "submit", function (event) {
            var handlerReturnValue;
            var value = valueAccessor();
            try { handlerReturnValue = value.call(bindingContext['$data'], element); }
            finally {
                if (handlerReturnValue !== true) { // Normally we want to prevent default action. Developer can override this be explicitly returning true.
                    if (event.preventDefault)
                        event.preventDefault();
                    else
                        event.returnValue = false;
                }
            }
        });
    }
};