Bind to float / numbers. ("") is added to json model

https://groups.google.com/forum/#!topic/knockoutjs/5WcUS2Od9NM

by rniemeyer

HTML

<script src="http://knockoutjs.com/js/jquery.tmpl.js"></script>
<script src="http://knockoutjs.com/downloads/knockout-2.2.1.js"></script>
<label>Bad </label><input data-bind="value: units" />
<hr/>
<label>Good </label><input data-bind="value: unitsForEditing" />
<hr/>
<div data-bind="text: ko.toJSON(units)"></div>

JavaScript

var viewModel = {
    units: ko.observable(2.50)
};

viewModel.unitsForEditing = ko.dependentObservable({
    read: function() {
      return viewModel.units();  
    },
    write: function(value) {
         viewModel.units(parseFloat(value));   
    }
});

ko.applyBindings(viewModel);