title: Can I rely on Referer HTTP header?
body: <p>Can I rely on <code>Referer</code> HTTP header in my web application? I want to check if the user came from a particular domain/webpage, and if he or she did, then change the layout of my site accordingly.</p>
  
  <p>I know that people can disable <code>Referer</code> in their browsers. Any ideas how often users do that? Can I rely on <code>Referer</code> being present in 99%?</p>