Generic Web handler (*.ashx) The default HTTP handler for all Web handlers that do not have a UI and that include the @ WebHandler directive. This version is more recently written, floating on the page, to see it working click here
This version is often found on Microsoft Programming Pages, to see it working click here and then view source to copy the code needed.

Above are two presentations of the Microsoft Translator Widget and are documented here Microsoftİ Translator on the bing search engine website. For the widget to work either of the following: <span id='MicrosoftTranslatorWidget'></span> or <div id='MicrosoftTranslatorWidget'></div> must appear on your website page. Second, the widget requires specific javascript for it to function.

Please note to display both styles above on the same page they are presented inside an <iframe> and can produce some side effects if tested from this page.
Both seem to be quite good at maintaining the context of the translation between the frames and this page.
Keystroke Form Handling
This Page does some data type validation. It uses addEventListener with keydown to control the input fields by keystroke. The main feature is pressing F2 invokes a Help Page for the specific prompt. Really of course it uses the # and <a name="Token"> which amazingly is not HTML5 supported.