title: how to start up a desktop application in client side
body: <p>In my web page, I have to start a desktop application on the client's computer if it's installed. Any idea how I can do this?</p>
  
  <p>If the application is MS Office or Adobe Reader, I know how to start them, but the application I want to start is a custom application. You can not find it on the internet.</p>
  
  <p>How can I open the application?</p>