Knockoutjs.com - Hello World Example

http://knockoutjs.com/examples/helloWorld.html

HTML

<script src="http://knockoutjs.com/downloads/knockout-3.0.0.js"></script>
<input type="text" data-bind="value: myField">
    
<input type="button" value="Click me" data-bind="click: buttonClicked">

JavaScript

var ViewModel = function() {

   this.myField = ko.observable('abc');
    
   this.buttonClicked = function() {
      this.myField('azertyuiolkjhgfdsseryuujnbvcxsssx');
   }
  
};
 
ko.applyBindings(new ViewModel());