asp.net mvc - Button click data-bind is not working with knockout -

i cannot following piece of code fire button click call save. using asp.net mvc knockoutjs. new knockout , mvc. missing here? in advance.

cshtml

@section scripts {           <script src="~/scripts/knockout-3.4.0.js"></script>   <script src="~/scripts/knockout.mapping-latest.js"></script>   <script src="~/customscripts/bookingviewmodel.js"></script>    <script type="text/javascript">        var bookingviewmodel = new bookingviewmodel(@html.raw(data));        ko.applybindings(bookingviewmodel);    </script> }  <div class="content">  <button class="btn btn-primary pull-right" data-bind="click: save"><i class="fa fa-check"></i> save booking</button> </div> 

bookingviewmodel.js

bookingviewmodel = function (data) {     var self = this;     ko.mapping.fromjs(data, {}, self);      self.save = function () {         $.ajax({             url: "/booking/save",             type: "post",             data: ko.tojson(self),             contenttype: "application/json",             success: function (data) {                 if (data.bookingviewmodel != null) {                     ko.mapping.fromjs(data.bookingviewmodel, {}, self);                 }             }         });     }   }