title: How to track variable changes in PHP
body: <p>Good day.</p>
  
  <p>I've been working on project that contains many variables and sessions and where most of the job is done "under the hood" and via ajax.</p>
  
  <p>The problem is that I try to debug my project and I just can't find any way to track and log changes that're made to a certain variable.</p>
  
  <p>I've been trying to use firephp and xdebug but they don't show when changes where made to the variable, only its final value.</p>
  
  <p>Any solution?</p>