title: PHP: Update variable when link is clicked
body: <p>I would like to update a variable when a html hyperlinked text is clicked. 
  Was wondering how I should approach this.</p>
  
  <p>I have two seperate page options, a and b.</p>
  
  <p>I would like to have "You are using A, CLICK HERE to change to B"
  If they click, the global variable $option would update to == B.</p>
  
  <p>Is this possible to do without the use of Javascript?</p>