twowaybinding.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Sample Knockoutjs App</title>
</head>
<body>

<p data-bind="text:message">Output Section</p>
<input data-bind="textInput:message" type="text">
<button data-bind="click:getMessage" >Click me</button>

<script type='text/javascript' src='./js/knockout-3.5.0.js'></script>
<script>
  function View(){
      this.message = ko.observable("Start");
      this.getMessage =  function(){
         alert("message is " + this.message());
      }
  }

  ko.applyBindings(new View());
</script>
</body>
</html>