javascript and activex control communication

I saw a website using below syntax to listen to the event from an activeX control, I am wandering where I can find the reference for the definition of the "for" and "event" keywords in "script" element? Is it W3C standard?

<script开发者_如何学Python language="javascript" type="text/javascript" for="DopvsPlugInCtrl" event="NotifyLocalPort(localport)">
            newport = localport;
    </script>

for and event attributes are not W3C. They are specifically designed for IE to handle ActiveX. You may take a look at this article.