title: how to load a different html page without refreshing the page or changing the url?
body: <p>I want to load an html page without refreshing the page or changing its url.
  So for example, If I am at <code>http://localhost/sample/home</code> and I want to navigate to contact us page, I click on the contact link and the contact page content gets loaded without refreshing the page or changing the url.</p>
  
  <p>How this can be done?</p>