Q:

Tracking user browser history without server-side code

I'm developing a registration form that leads users to a "Thank you" confirmation page. On this confirmation page, I'd like to have a button that redirects users to wherever they were prior to the registration page. 
The only catch is that my client needs this to be done entirely on the front-end, with HTML5 and JavaScript. 
Given these constraints, what's the most efficient way to generate a link that sends the user to where he/she was two pages ago? 

A:

If I understand your question correctly, you can just do this when the button click: 
<script>
function goBack()
  {
  window.history.go(-2)
  }
</script>

<body>
<button onclick="goBack()">Go Back 2 Pages</button>
</body>

This was directly from example of w3school http://www.w3schools.com/jsref/met_his_go.asp

