title: Custom protocol detection across browsers
body: <p>How to check from browser  whether the desktop app is installed or not, as if not installed user will be shown a installer link and  if not we would just start the desktop app, the challenge here we are using custom protocol handler concept to detect whether the custom url is registered, but this only works in firefox and ie11 on win8. </p>
  
  <p>On chrome there is no way to detect the proptocl handler being present, based on blurring of window will not work incase user checks the donot show window option, then the custom url alert will not be shown and there is no way to know the custom url is registered. Same behaviour goes for ie11 on win7.
  could anyone help here </p>