knockout.js simple binding

koOne.html

<p>
<h1> welcome to   <span data-bind="text:companyName" </span></h1>
</p>

<script type="text/javascript" 
src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.0/knockout-min.js"></script>

<script type="text/javascript">

var viewModal =  function (){

  this.companyName = 'WebKul Software Private Limited';
};

ko.applyBindings(viewModal);  
</script>