是否可以确定客户端是否安装了某个ActiveX控件？

function hasFlash() {
  var hasFlash = false;
  var plugins = navigator.plugins;
  for (var i = 0; i< plugins.length; i++) {
    if (plugins[i].name.indexOf('Shockwave Flash') !== -1) {
      hasFlash = true;
      break;
    }
  }
  return hasFlash;
}

if (hasFlash()) {
  console.log('Flash Player is installed');
} else {
  console.log('Flash Player is not installed');
}