title: Code to detect if a user has Antivirus installed from browser?
body: <p>I'd like to be able to use any language from a web browser (PHP, ASP, Flash, Javascript, Java etc) to detect if a user has antivirus installed.</p>
  
  <p>I'm researching the possibility of only letting a user log into a Virtual Private Network from machines which have up to date antivirus installed.</p>
  
  <p>Can this be done, if so how?</p>
  
  <p>Thanks.</p>