Show a message if the browser is not internet explorer 9 or greater

Question

I would like to show my users a bar that looks like this, if:

1. Browser is not IE; or
2. Browser is IE but is version 8 or earlier

Answer 1

Checking if browser engine is Trident 6+ (IE 9, 10, 11) should do (demo):

(function () {
  var trident = {
    string: navigator.userAgent.match(/Trident\/(\d+)/)
  };

  trident.version = trident.string ? parseInt(trident.string[1], 10) : null;

  if (!trident.string || trident.version < 6) {
    document.body.innerHTML = '
Not supported.
' +
      document.body.innerHTML;
  }
})();

However, the sniffing may break in IE 11 final or future versions if Microsoft will decide to change userAgent string.